I originally posted this as a comment on one of Andrew McAfee's blog posts, then realised I should be putting it on here, too.
I've been trying to get a project team to use E2.0 tools recently. It's been harder work than I expected. We've been using Google docs to hold project documentation. This includes a spreadsheet that is the project plan. I had to switch to Zoho for the plan, because it became too big to upload to Google Docs. So that made 2 places to look, and 2 applications to learn. I thought both Google Docs and Zoho would be 'no-brainers' to get the hang of, but some people found it difficult. And we've had glitches, both human (eg my forgetting to give the right people access to a document) and technical (a bug in Google preventing editing of access permissions).
However, despite all these issues I think we've begun to see some benefits, and no-one has refused to play ball out of our small team of half a dozen or so. It's also been interesting that, some sensitive customer data apart (which was kept off the system) there has not been too much concern about putting the project data onto third party servers.
Incidentally, the team comprises the customer for a system, the supplier, and myself as an independent project manager. The fact that we're from three different organisations made it beneficial to use SaaS platforms (no access problems), but it also meant I didn't have the power to make the choice of tools and methods a matter of diktat.