The setup is as follows (see Knosos.be) the folksonomies of people describe their expertise. This information is then combined with the relations between the people, resulting in the visualisation of communities, leading to collaboration and knowledge sharing.
The folksonomies are the boundary objects, describing a person as he really is (or wants to be seen by other people). They are the points were personal environments meet.
The strength in my opinion is in the combination of folksonomies (see http://del.icio.us) and networking (see http://www.linkedin.com) and leveraging this combined information to actual collaboration and knowledge sharing.
Analysis of the tags used and created by a group show specific expertises or can point at gaps in the knowledge base of a team or an organization.