Um ... yes ... it's a legitimate forum in which anonymous people post their widely-ranging (informed and uninformed) opinions about stocks.
I have no doubt there are some legitimate investors who post; and I have little doubt that there are pumpers and other manipulators who benefit from creating short-term highs and lows.
Are the MOD's legit? I don't know. I know that in the past the SEC has cracked down on specific forums and their MODs for manipulation, but I don't have reason to believe all forum MODs are suspect.