buckworks - 4:01 pm on Jan 5, 2005 (gmt 0)

If you're selling listings, Chabbs's comment is the reason I'd say to use Adsense (or other ads) from Day 1 if you're going to run them at all.

That way, there's no misrepresentation about what people would get if they bought a listing, and people can make their own decisions about whether they want to compete with Adsense or other ads.