Thanks to Bill Ives and his Portal and KM blog, I've been able to get the gist of the Forrester TechRadar For Vendor Strategists: Enterprise Web 2.0 without paying the $379 it costs to read the whole thing (hurrah!)
Bill reviewed the report and his highlights mention that usage of Enterprise 2.0 software has produced significant success with social networks and wikis, moderate success with blogs, forums, mashups, prediction markets, RSS and widgets (don't they make your beer bubbly?) and minimal success with microblogs, podcasts and social bookmarks.
I'd agree that people appear to connect with social networks and wikis more than, say, podcasts and RSS (vastly underutilised if you ask me), but I would have to read the report to know why the distinction between social networks and forums. Any road up, the top and bottom of it is that in terms of these collaborative software applications "Some were just starting on their journey (microblogs), others had reached their high point (podcasts and forums) but none were on their way down". So the fact that the public sector is only just opening its doors to these tools is not necessarily bad - looks like enterprise 2.0 is no fad.