The only way to get people to continue to incorporate any tool in their life is their interest in that tool. A very obvious statement I know but one about which I have to keep reminding myself. My “test case” blog is a manual for our student workers that may also have a calendar. The students will be able to go online and see their schedule, see any new information and maybe, one day, be able to edit their own calendar.
For other purposes I see it as a tool for short term projects-for example, discovery and evaluation of federated search engines or ILS. I have seen how the effective sharing is used to create an annual report, a wiki for every year. A great digital history project.
As a ongoing collaboration tool it seems to be most useful as an online document storage center. Document are clustered by topic and shared by all.
As a sidebar comment-there are incestuous connections going on in the web 2.0 world! The lists I subscribe to subscribe to each other and make a huge daisy chain of posts.