I was first in line for an ad posted by tat2u here.
I immediately left an IM with him after replying. I left another IM and sent an email through the site a couple days later. I sent a final IM and email the week after the ad was posted. Each time I sent another IM I responded to the ad thread.
Tat2u logged on many times during this time, but never once responded to any of my IMs, emails or replies. From the comment of another member who posted in the thread it seems he didn't respond to anyone's IMs or emails.
If he wanted to back out, that's fine, but don't start a "for sale" thread and then not respond when someone accepts your offer.