possession (something that can be used) vs. property (something that can be sold). 
From the Wikipedia:
"In law, possession the control a person intentionally exercises toward a thing. In all cases, to possess something, a person must have an intention to possess it. A person may be in possession of some property (although possession does not always imply ownership). Like ownership, the possession of things is commonly regulated by states under property law." (http://en.wikipedia.org/wiki/Possession_%28law%29)
Christian Siefkes: Peer Production is based on Possession, not Property
"Peer production is based on commons and possession (not on property). Benkler talks about “commons-based peer production” to emphasize the important role of the commons (goods and resources without owners who can control how they can be used). Generally, commons such as free software and open knowledge play an important role as input or output (or both) of peer projects.
Where things are not commons, they generally matter as possession (something that can be used), not as property (something that can be sold). In current peer projects, resources such as computing power and Internet access are typically privately owned, but they are used and shared for reaching the goals of the projects, they aren’t employed for financial gain. And, as noted above, participation in peer projects is motivated by use value, not by exchange value — goods are produced to be used (as commons or possession), not be be sold (as property)." (http://www.keimform.de/2008/01/21/material-peer-production-part-0-traits-of-peer-production/)
Relevance to Usage and Resource Allocation
"One issue where this becomes relevant is the question of _long-term vs. short-term usage._ When projects expect people to make contributions in order to get the things they want, there are cases where the length of usage should be taken into account. Otherwise, people who want to use something for a limited period of time would be put at a serious disadvantage, since they would have to contribute just as much as if they wanted to use it "forever." When the expected "lifespan" of a good exceeds the expected time of usage by any given person, it might thus be appropriate to tie the required contributions to the length of usage, sharing the overall effort between all who use it over time. For example, a project or local association organizing housing for its members might prefer to require contributions for living in a house or apartment for a certain amount of time (instead of for living there forever), thus spreading the effort necessary for building and maintaining houses among all the people who live there over time.
The difference between property and possession is also relevant for the problem of _resource allocation._ In an economy where everything is based on commons and possession instead of property, it would not make sense to treat natural resources as property--to rely on buying and selling to allocate them. In fact, it would not even be possible: if nothing apart from resources is sold, how should those who lack them be able to buy them?
The alternative is to treat resources like everything else: as commons and possession. Since specific resources are typically bound to the location where they occur, they might be _managed_ by the _local associations_ (cf. previous part) they are in, but they won't be _owned_ by anybody. Instead, they are _commons_ when they are not used; they become the _possession_ of some person or project using them for some purpose; and they revert to the _commons_ when they are no longer used (provided they haven't been used up).
Since resources are commons, and since any local association is unlikely to have enough of _all_ the resources its members need, it makes sense for the various local associations to _pool_ their resources. They can do so by using the shared allocation system of an existing _ distribution pool_ (cf. previous part) to distribute the available resources of all participating local associations among all their inhabitants.
When resources are pooled, they can be allocated to those who want them in a similar way to other goods distributed through a d-pool. When there is enough of a resource available for all who want to use it, everybody can get what they want for free, which is essentially a _flat rate_ model. If there is more demand than can be satisfied, resources can be "auctioned off" in the same way as products: the resource will be assigned to the people or projects willing to contribute most weighted labor to the d-pool in order to get it _(preference weighting)._ If a project acquires resources that are not available for free (flat rate), it can add the weighted labor necessary to get them to the tasks the project members need to handle, so this additional labor will be distributed among them in the usual way.
Remember that resources are considered as _commons,_ not as the property of the local associations where they occur. They are just made available as additional goods to be distributed through a d-pool. If a resource is auctioned off at a high cost, the association of origin won't benefit in any special way; instead, all the other goods distributed through the same pool will become slightly cheaper. This follows from the fact that resources are treated just like other goods that are distributed through a d-pool: if a project successfully distributes one of its products through the pool, the _effort_ (in weighted labor) required to produce it will be recognized as a contribution to the pool. But natural resources are not produced, they just exist, so the production effort to be recognized is zero."
What is the difference between private property and possession?
"Anarchists define "private property" (or just "property," for short) as state-protected monopolies of certain objects or privileges which are used to control and exploit others. "Possession," on the other hand, is ownership of things that are not used to exploit others (e.g. a car, a refrigerator, a toothbrush, etc.). Thus many things can be considered as either property or possessions depending on how they are used.
To summarise, anarchists are in favour of the kind of property which "cannot be used to exploit another -- those kinds of personal possessions which we accumulate from childhood and which become part of our lives." We are opposed to the kind of property "which can be used only to exploit people -- land and buildings, instruments of production and distribution, raw materials and manufactured articles, money and capital." [Nicholas Walter, About Anarchism, p. 40] As a rule of thumb, anarchists oppose those forms of property which are owned by a few people but which are used by others. This leads to the former controlling the latter and using them to produce a surplus for them (either directly, as in the case of a employee, or indirectly, in the case of a tenant).
The key is that "possession" is rooted in the concept of "use rights" or "usufruct" while "private property" is rooted in a divorce between the users and ownership. For example, a house that one lives in is a possession, whereas if one rents it to someone else at a profit it becomes property. Similarly, if one uses a saw to make a living as a self-employed carpenter, the saw is a possession; whereas if one employs others at wages to use the saw for one's own profit, it is property. Needless to say, a capitalist workplace, where the workers are ordered about by a boss, is an example of "property" while a co-operative, where the workers manage their own work, is an example of "possession." To quote Proudhon:
"The proprietor is a man who, having absolute control of an instrument of production, claims the right to enjoy the product of the instrument without using it himself. To this end he lends it." [Op. Cit., p. 293]
While it may initially be confusing to make this distinction, it is very useful to understand the nature of capitalist society. Capitalists tend to use the word "property" to mean anything from a toothbrush to a transnational corporation -- two very different things, with very different impacts upon society. Hence Proudhon:
"Originally the word property was synonymous with proper or individual possession. It designated each individual's special right to the use of a thing. But when this right of use . . . became active and paramount -- that is, when the usufructuary converted his right to personally use the thing into the right to use it by his neighbour's labour -- then property changed its nature and this idea became complex." [Op. Cit., pp. 395-6]
Proudhon graphically illustrated the distinction by comparing a lover as a possessor, and a husband as a proprietor! As he stressed, the "double definition of property -- domain and possession -- is of highest importance; and must be clearly understood, in order to comprehend" what anarchism is really about. So while some may question why we make this distinction, the reason is clear. As Proudhon argued, "it is proper to call different things by different names, if we keep the name 'property' for the former [possession], we must call the latter [the domain of property] robbery, repine, brigandage. If, on the contrary, we reserve the name 'property' for the latter, we must designate the former by the term possession or some other equivalent; otherwise we should be troubled with an unpleasant synonym." [Op. Cit., p. 65 and p. 373]
The difference between property and possession can be seen from the types of authority relations each generates. Taking the example of a capitalist workplace, its clear that those who own the workplace determine how it is used, not those who do the actual work. This leads to an almost totalitarian system. As Noam Chomsky points out, "the term 'totalitarian' is quite accurate. There is no human institution that approaches totalitarianism as closely as a business corporation. I mean, power is completely top-down. You can be inside it somewhere and you take orders from above and hand 'em down. Ultimately, it's in the hands of owners and investors." Thus the actual producer does not control their own activity, the product of their labour nor the means of production they use. In modern class societies, the producer is in a position of subordination to those who actually do own or manage the productive process.
In an anarchist society, as noted, actual use is considered the only title. This means that a workplace is organised and run by those who work within it, thus reducing hierarchy and increasing freedom and equality within society. Hence anarchist opposition to private property and capitalism flows naturally from anarchism's basic principles and ideas. Hence all anarchists agree with Proudhon:
"Possession is a right; property is against right. Suppress property while maintaining possession." [Op. Cit., p. 271]
As Alexander Berkman frames this distinction, anarchism "abolishes private ownership of the means of production and distribution, and with it goes capitalistic business. Personal possession remains only in the things you use. Thus, your watch is your own, but the watch factory belongs to the people. Land, machinery, and all other public utilities will be collective property, neither to be bought nor sold. Actual use will be considered the only title -- not to ownership but to possession." [What is Anarchism?, p. 217]
This analysis of different forms of property is at the heart of both social and individualist anarchism. This means that all anarchists seek to change people's opinions on what is to be considered as valid forms of property, aiming to see that "the Anarchistic view that occupancy and use should condition and limit landholding becomes the prevailing view" and so ensure that "individuals should no longer be protected by their fellows in anything but personal occupation and cultivation [i.e. use] of land." [Benjamin Tucker, The Individualist Anarchists, p. 159 and p. 85] The key differences, as we noted in section A.3.1, is how they apply this principle.
This anarchist support for possession does not imply the break up of large scale organisations such as factories or other workplaces which require large numbers of people to operate. Far from it. Anarchists argue for association as the complement of possession. This means applying "occupancy and use" to property which is worked by more than one person results in associated labour, i.e. those who collectively work together (i.e. use a given property) manage it and their own labour as a self-governing, directly democratic, association of equals (usually called "self-management" for short).
This logically flows from the theory of possession, of "occupancy and use." For if production is carried on in groups who is the legal occupier of the land? The employer or their manager? Obviously not, as they are by definition occupying more than they can use by themselves. Clearly, the association of those engaged in the work can be the only rational answer. Hence Proudhon's comment that "all accumulated capital being social property, no one can be its exclusive proprietor." "In order to destroy despotism and inequality of conditions, men must . . . become associates" and this implies workers' self-management -- "leaders, instructors, superintendents . . . must be chosen from the labourers by the labourers themselves." [Proudhon, Op. Cit., p. 130, p. 372 and p. 137]
In this way, anarchists seek, in Proudhon's words, "abolition of the proletariat" and consider a key idea of our ideas that "Industrial Democracy must. . . succeed Industrial Feudalism." [Proudhon, Selected Writings of Pierre-Joseph Proudhon, p. 179 and p. 167] Thus an anarchist society would be based on possession, with workers' self-management being practised at all levels from the smallest one person workplace or farm to large scale industry (see section I.3 for more discussion).
Clearly, then, all anarchists seek to transform and limit property rights. Capitalist property rights would be ended and a new system introduced rooted in the concept of possession and use. While the exact nature of that new system differs between schools of anarchist thought, the basic principles are the same as they flow from the same anarchist theory of property to be found in Proudhon's, What is Property?.
Significantly, William Godwin in his Enquiry Concerning Political Justice makes the same point concerning the difference between property and possession (although not in the same language) fifty years before Proudhon, which indicates its central place in anarchist thought. For Godwin, there were different kinds of property. One kind was "the empire to which every [person] is entitled over the produce of his [or her] own industry." However, another kind was "a system, in whatever manner established, by which one man enters into the faculty of disposing of the produce of another man's industry." This "species of property is in direct contradiction" to the former kind (he similarities with subsequent anarchist ideas is striking). For Godwin, inequality produces a "servile" spirit in the poor and, moreover, a person who "is born to poverty, may be said, under a another name, to be born a slave." [The Anarchist Writings of William Godwin, p. 133, p. 134, p. 125 and p. 126]
Needless to say, anarchists have not be totally consistent in using this terminology. Some, for example, have referred to the capitalist and landlord classes as being the "possessing classes." Others prefer to use the term "personal property" rather than "possession" or "capital" rather than "private property." Some, like many individualist anarchists, use the term "property" in a general sense and qualify it with "occupancy and use" in the case of land, housing and workplaces. However, no matter the specific words used, the key idea is the same. (http://anarchism.pageabode.com/afaq/secB3.html#secb31)