There's been a number of interesting posts about "Enterprise 2.0" (recently deleted from Wikipedia!). Dion Hinchcliffe captures the key ideas (bolding mine):

One of the big attractions of things like Enterprise 2.0 is that it articulates the potential of using Web 2.0 techniques behind (and across) the firewall for greatly improved capture and sharing of organizational knowledge.  Retention and use of the volumes of insight, facts, solutions to common problems, and other tacit experience that is normally lost when an employee leaves or changes positions is one major benefit.  And not only is Web 2.0-style information capture encouraged with Enterprise 2.0, but the application of enterprise search to relentlessly find it again.

and

Business information that would otherwise be hoarded en masse within Microsoft Office documents of every description, e-mails, and data files stored privately in user's computers, accounts, and home directories — thereby severely curtailing its utility to the rest of the organization — can and often should be easily opened up and shared.

There's also been a number of posts about barriers to adoption (Jerry Bowles, Dan Farber, Rod Boothby) of Office 2.0/Enterprise 2.0 technology. One thing I note missing is that no-one's really made the case that it's cost effective, that the amount of time spent "enterprise 2.0ing" information by blogging and sharing and so forth brings a net organizational benefit. Obviously, we believe it and once it's working everyone else will believe it (and wonder what the hell was wrong with everyone's thinking back in 2006).

The likely case is that many of these technologies will be adopted first at a departmental level, prove their worth and then work their way upwards, just like with Intranet technologies in the 95-98 period.