why should they be investigated - they are just a platform for people interested in and writing about stocks. It's up to each and every investor to educate himself. And there's plenty of useful information on seekingalpha.
actually a good trader should have always a close look on new sa articles as some contributors really move stocks. And once the momentum hype is gone these stocks bring profits a second time when playing them short.
don't blame seekingalpha for the dumbness of uneducated investors - they fully get what they deserve