I only go to three
I usually visit BPL, Hammock forums, and Whiteblaze. The knowledge base at BPL is huge and falls right in line with my light hiking philosophy. Hammock Forums has a great MYOG section and is about the friendliest site I've ever seen. Whiteblaze has a ton of AT related info of course, which is where I hike typically. All three site have a lot to offer.