Count commercial real estate professionals among them. They'reusing Facebook to market themselves and their firms, cultivatecontacts and generate interest in projects and deals.

It's not particularly surprising. Facebook announced late lastmonth that it now has about 100-million active users worldwide,with the fastest growing group those 25 and older. FacebookAdvertising gives businesses an opportunity to reach thoseusers through "targeted advertising to the exact audiences theywant," the company says.

They can also create Facebook Pages, which give users--with aninterest in a particular business--the opportunity to interact withit in much the same way they interact with their friends, or formFacebook groups to link users with similar interests. The bestpart, company executives note, is that they can create a presenceon Facebook-and potentially generate buzz about products, services,deals or themselves-free of charge.