According to a recent Nielsen report:
RSS users are significantly more engaged in online news than non-users, visiting an average of 10.6 news sites compared with 3.4 news sites for non-users…Not only do RSS users visit more news Web sites than non-users, they also visit those sites more frequently. RSS users visited the top 20 news Web sites nearly three times as often as non-users and all other news Web sites four times as often. This means that sites outside of the top 20 properties may be among the greatest beneficiaries of RSS.
Those law firms and professional service businesses not incorporating RSS into their marketing plans are clearly missing the boat.