At work we set up an internal install of Wordpress MU to see about getting folks blogging. In the past I have found no real value (in the cold hard cash sense of the word) in companies blogging, but I do believe it is helpful. One aspect of blogging that I find to be very helpful is the opportunity to write ideas. Typing is just slow enough to force the mind to really see all the details. In general, it seems to help one become a better thinker.
I truly doubt there will ever be a time where blogging will be a source of income for most companies. It seems obvious though that companies should utlize blogging as a means of self improvement for knowledge workers.