I would address some comments about this article. The first one is a criteria of reliability used by wikipedia: does that information have a Geographical Bias? I think yes. Twitter users are mainly US Americans (51.6%) ref: http://www.alexa.com/data/details/traffic_details/twitter.com and the integration of public web 2.0 websites into corporate context is mainly the case in the US also. In Europe, we are much more afraid of
integrating Facebook, twitter, LinkedIn, Del.ico.us in companies. This websites are often blocked, just because people spend too much time in poking, writing on walls, etc…
Further, the concern about being traced and tracked, everybody knowing every step we do, is much more present in Europe (inside and outside of corporate context).
I perfectly agree that this is something we have to worry about also in Europe. Giving guidelines about the use and the risk of using public web2.0 tools in corporate context and calling for professionalism still is the best solution.
The force of Enterprise 2.0 is not to use public websites in corporate context. It is using (nearly exclusively) behind the firewalls, technologies people are used to. If people are confident with this kind of technologies, they are more able to use it efficiently, with few formation and a high adoption curve.

There is one point I generally do not agree with you, it is about the security concern towards wikis.
Why are companies like IBM, HP, Dresdner Kleinwort (consider the importance of Bank Secrecy) and the US Intelligence (Intellipedia), using wikis if it represents a uncontrollable threat and important security leak?