Mention social networking and most people immediately think of sites like Facebook, MySpace or Bebo which let people create lists of friends, send messages to each other, share photos or music, join groups with like-minded-individuals and just generally keep in touch.

Images of industriousness rarely spring to mind, yet many organizations have realized that it's not all just super-poking and games of Scrabulous, and want to use their own social networks for the benefit of their businesses.

The potential for social networking tools to connect huge numbers of people has been clearly illustrated. Companies want to harness that power themselves, and not just for marketing or recruitment, but also for internal communications and collaboration.

One HR executive recently, rather mournfully, said to me, "Fifty per cent of our staff are on Facebook. Why can't we get that kind of buy-in?" Although Facebook is primarily a tool for organizing your personal life, people also use it for business and, increasingly, companies realize that they have to provide such tools internally or else employees will communicate over the web, potentially risking sensitive company data.

Another significant driver pushing companies to adopt social networking tools is the need to locate expertise within companies whose employees are dispersed across many locations and time zones, a problem exacerbated by restructured offices that emphasize teleworking and hot-desking. It was this, along with the emergence of Web 2.0, that formed the backdrop to IBM's exploration of social networking.

"One of the most important things within IBM is finding expertise," says Alastair MacKenzie, Lotus Software brand executive at IBM.

"It is fundamentally important to us both in terms of our efficiency and our competitive advantage in the marketplace."

IBM started in the most logical place: Blue Pages, its internal phone directory, to which it added profile pages that employees could update. Now those profiles can be tagged with keywords.

"We started hot-desking seven or eight years ago, and we became unable to find people [within the organization]," says Brendan Tutt, social networking subject matter expert at IBM.

"So we had to build a tool to enable us to find people and the skills they have. Having found them we can tag them with keywords useful to us. Tagging is a very big part of our internal tools: tagging yourself, tagging documents, or tagging people."

But Blue Pages is not just a way to find people by keyword, it is also a way to research a particular person or subject area, by pulling together blog posts, bookmarks (saved in a Del.icio.us-like social bookmarking application called Dogear), and documents related to that person or subject tag. This gives the searcher not just a good overview of how someone describes themselves, but how they are defined by others, and by their own actions and interests.

These interconnections are also described in a graphical view which shows how people are linked together, and thus who to approach for an introduction to required expertise. Social network mapping exposes the network's structure, so it's easy to see who is best connected in a given community.