Notes on the current rules from my Bladeforums blog:
Bumping your Exchange forum thread:
it ain't gonna happen! The current forum settings in the Exchange present all threads in chronological order of the original post. No further posts in these threads move them any higher. You are allowed to repost after 14 days.
11/15 Update: Based on feedback, we're trying a new format for the Exchange forums - we're sorting threads by Thread Started time instead of Last Post time. What does this mean? Threads are no longer going to be affected by bumping or replies - threads will still show up in the order that they were created.
If you prefer to sort threads by the time that the last post was made, you can, just select the option at the bottom of each forum screen.
Update on reposting:
SECTION 3 - Rules for Sellers / Traders / Service Providers (hereafter referred to as "Sellers"):
1.Rules for everyone:
[ ... ]
16. REPOSTING / RELISTING: You must wait two (2) weeks (14 days) to relist items for sale after the first time they have been listed. Don't try to circumvent this, your sale will be deleted, and your account will be locked.