(nods) Yeah, that's been my experience too, though I've often suspected that companies like Google probably have a lot of research on the subject lying around that might be informative.

Some friends of mine did some experimenting along these lines when doing distributed software development (in both senses) and were somewhat startled to realize that Dark Age of Camelot worked better for them as a professional conferencing tool than any of the professional conferencing tools their company had. They didn't mention this to their management.