Know-How Exchange : Website Critique

I recently began doing PR work for a client who offers web chat services for car dealership web sites. You know what I'm talking about: a person goes to the dealerships web site and in less than a minute a chat window appears, complete with static image and name of an "attractive young woman."

I've been looking, but can't find much research or serious discussion on web site chat, particularly for B-to-C sites. (Frankly, I can see pros and cons for it, depending on the type of web site.) Please share your thoughts and experiences and/or send links with relevant content. I'm really looking for research results more than anecdotes.