(i.e. WoWInterface.com Curse.com etc are all good)
Adding a new post to an existing thread that's at the bottom of the page effectively bumps it to the top. Some people just say bump to do this so their thread goes to the top, however this does not get it answered quicker as Blizzard go by thread creation date and answer in order earliest first.
Bumping is against the forum rules and should be avoided where possible.
As Shammoz has already explained, while we don’t specifically support or recommend the use of in-game add-ons (in fact, when it comes to reducing in-game issues and UI related corruption, I’d almost actively recommend against them!), there’s certainly nothing wrong with making use of legitimate add-ons to enhance your gameplay if you so choose.
Any add-ons are obviously downloaded and used in-game at your own risk, but if you ensure you’re using well respected sites and keep them up to date then you should hopefully only ever experience disruption or issues following on from major content patches or similar (and you should be prepared to potentially remove or disable them at such times!). :)