I have a love-hate relationship with Craigslist. I hate that its interface hasn't evolved since 1995, that posting an ad is always a crapshoot, and that there's zero support available, but I love that it's still so highly trafficked that you can post an ad for almost anything and get flooded with responses. Whenever we have a job opening, we almost always post our job ad to Craigslist, amongst other job boards.

Using GMass, the disjointed mess of handling responses to a Craigslist ad becomes navigable and, dare I say, easy for Gmail users. No need to create a separate account to receive CL responses, and no response is left hanging.