Among the recent job posters I noticed exclusively using LinkedIn -- Google, Cisco Systems, and Kaiser Permanente. Big companies from a variety of industries. I used to see just a tiny fraction of the job listings carrying asterisks, but that percentage is definitely increasing.
What's this all about? My instinct is that employers are trying to cut down on the flood of resumes they're getting if they post on any of the big job portals such as Monster.com or Yahoo!Hotjobs. Let's face it, it's not useful to get 500 responses to an ad for a single job. So posting only on a more niche site, or in a more targeted way, may be a good way to cut down on the resume flood.
Are you hiring? If so, how are you finding qualified candidates without drowning in a sea of resumes? Small businesses ought to be able to target their hiring searches just like the big companies do. Sifting through mountains of resumes isn't something most small businesses have time for, and if you're hiring, it's because you're already short of time!