We used to use a site called ECWID to host our own on-line store (We use prestashop now - but that is another story)
They have a GREAT forum where members can suggest new features for the site, and other members can vote. This way popular ideas get to the top and are then implemented more quickly
Each member gets allocate a number of votes to cast (12 i think) and you can add up to 3 votes per feature. Once your votes run out yo either wait until one of your voted on features is implemented or cancelled, in which case you get them back. Or you can remove your own votes and move them elsewhere
It really works well and lets the developers know what is needed for the site
I think it would work really well here at Ebid, where it often seems ideas are just left in limbo and we have no way of knowing if the devs have taken the suggestions on board
http://ideas.ecwid.com/forums/22031-ideas-ecwid
Incidentally, they also allow members to fund an idea. That way the devs drop everything and just work to implement that idea. A number of "chip in " campaigns were successful in getting things implemented even faster