I just read an interesting overview of Tripwolf.com on Eyefortravel:

[Tripwolf.com] is backed by MairDumont, Europe's largest publisher of travel guides including Baedeker, Dumont and Marco Polo... On tripwolf.com, professional travel content from MairDumont is combined with travel tips from knowledgeable travelers coined as "trip gurus". It combines professional editorial content with user-generated content from globetrotters worldwide.
I think Tripwolf is a site to watch. I've used it a little and it has some interesting features.