This is similar to what I suggested in eLearning Technology: Personal and Group Learning Using Web 2.0 Tools and eLearning Technology: Social Bookmarking Tricks for Group Learning
AARF has built interfaces to the bookmarking site del.icio.us, the photo sharing site Flickr, and Digg, a site where members vote on the importance of news stories. All three use tags, or something close.
AARF employees have learned to add the tag 'AARF' when they come across a web page (using del.icio.us), a photo (Flickr), or a news story (Digg) that they think will be of interest to their colleagues. Shortly after they add this tag, the bookmark (look at the top of the box), thumbnail of the photo (middle) or headline and description of the story (bottom) show up within the AARF E2.0 Intranet. So AARF has found a fast and low-overhead way to let its employees share Internet content with each other. It's also free; these interfaces with del.icio.us, Flickr, and Digg require no fees and no permissions. I find this simply brilliant.
Andrew has followed up on his original post with some concerns around security. Because the tags are visible globally, then other folks can see what is being tagged with AARF. This can be problematic. With some tools, e.g., Yahoo MyWeb, you can limit the visibility of your pages (or your tags) and I'd expect that to start happening with other tools as well. This is something I've discussed before: Yahoo MyWeb better than del.icio.us, rollyo, et.al. for Personal / Group Learning.
Both of Andrew's posts are definitely worth reading.