If you are like most people I have asked this question your response was probably something like ‘aren’t they the same thing?’, and of course the answer would be no, they are not and the primary distinction between them is in the value that is created from each.
Social networks are characterized by one to one connection versus a collective gathering virtually in one space to work on a single project or problem as is the case with collaborative networks. With the instance of the popular social networking site Facebook for example the value created is to the individual and the benefit of his/her connections. On the other hand a collaborative network such as MindTouch allows groups of people to collaborate efficiently and effectively to produce results that add value to the enterprise or collective as a whole rather than the individual.
That isn’t to say that social networks can’t benefit your business but rather that they will do so through one to many advertising and one to one contacts rather than through collective decision making and problem solving.
So keep in mind when/if you are considering integrating a networking application into your business enterprise: If you are looking for people (potential sales leads, recipients of advertising, potential future colleagues) go for a Social Network. If you want to connect the disparate groups (departments, divisions etc) to collaborate to address issues and projects with tangible results go with a Collaborative Network.