Photography forums, especially those that are centered around gear, are valuable for the following things: 1) user experience with a particular camera, lens, strobe, etc., 2) exchanging ideas related to the practical use of your specific gear, 3) asking for recommendations related to a potential purchase, and 4) sharing of images created with the gear being discussed. Just be sure not get to get sucked into the GAS (Gear Acquisition Syndrome) while browsing the forums.
Back in April, I decided I would completely cut myself off from the main forums I participated in since at least 2005. Looking back, I would say that the main I reason I left the forum was that I was essentially providing the forum, and the associated commercial website, with FREE content. That bothered me. Why should we spend our time writing free content for a commercial site? It was after this realization, that I came to the conclusion that I would stop participating and concentrate on two things instead. 1) Creating wonderful images and 2) writing for myself, not someone else.
Since that time, I have changed my position on the matter of photography forums. I really just needed a break and some clarity regarding photography, gear and goals. I promise, you will learn more about photography when you are actually actively engaged in the creation of images vs. discussing them online. You will also progress in your craft at a much faster pace if you were to pick up a good photography book/e-book, attend a quality workshop or read the blog post of successful photographers in the area of photography you are interested in.
So go ahead and participate in good forums and enjoy yourself. Just be sure you are creating images as well!