I am using Twitter and have already generated a few strong candidates for a few internal account manager jobs we are hiring. Several of the people following me on Twitter have also forwarded a few referrals for potential UMS Franchise owners that I am now speaking with! I feed my blog postings on RBC directly to twitter automatically via TwitterFeed.
Perhaps I'm simply more anal because I'm an engineer but I like to have a plan. My advice to Dennis was to use Twitter like a GrandMaster plays chess - always thinking several steps ahead rather than stream of consciousness. But then again, I may be different... ;)
Twitter is a great way for potential candidates to 'get to know you' and for you to be more approachable, more personal so that you are more familiar to them than some unknown recruiter. It lets you establish a connection more easily, and gets your name out there. I had several new candidates contact me who had been following me for awhile and knew I recruited in their space. When they were ready, they got in touch. I'm a big fan!
Dennis, I would say that there is a difference between being a recruiter and using twitter to generate placements and being a recruiter and using twitter to be part of a recruiting community. It's the same thing as recruiters who blog to generate placements and recruiters who blog to be part of a recruiting community. Both are very valuable things to do and both will yield results.