Web 2.0 resistance from Law Firms

Why are some Law Firms still not using Web 2.0 applications "behind their firewall"? and do you work at one of these firms? If so you might be interested in reading a summary of the Am Law Tech 2008 survey.

Penny Edwards from Headshift describes this as disappointing and I'm sure many people who are working with Web 2.0 applications on a daily basis will agree with this viewpoint. But why are so many law firms not yet doing Web 2.0? Mary Abraham has some thoughts on this subject in her post "Web 2.0 resistance in law firms" and I'm sure many others will as well.

Is it because as Mary says firms are looking at other areas rather then Web 2.0? or because the benefits of using Web 2.0 tools aren't clear or that there are too many issues associated with using these types of tools. What does everyone think?