#3 in the old classifieds forum rules listed here: http://geekhack.org/index.php?topic=31625.0
I believe it was also brought back up recently in one of the feedback threads but I have no reference to link to.
You have a point, but that looks more like a request (Please do this) than a rule.
Same with Bumping/"ttt", I do it, but I wait 24 hours. The "rule" isn't spelled out very well. There are people who post WTS/WTB threads who are not well known or their thread my get any attention due to being new, so a bump every 24 hours is fine. Otherwise their thread would get buried on page 5.
Oh and the above are meant as opinions, not facts lol
Edit - I'm sorry boost. I should have edited this into my last post
Edit2 - I really need to make some coffee