Goolge has just recently bought JotSpot.

Like iUpload, Blogtronix, Socialtext, Atlassian, WordPress, SixApart, and Teqlo, JotSpot represents a new generation in productivity tools that can be used in an enterprise setting. Another way to say this, is that Google's purchase of JotSpot could be viewed as the first major purchase of an Enterprise 2.0 / Web Office company.

It will be interesting to see how this impacts the growth and evolution of this field. Will Yahoo! and Microsoft rush in to snap up some of these other companies?