Any offshoot sports forum or blog that fails at its goal of being better than the original from which it was spurned. Usually denotes a spinoff site that attempts to be cozy with a corporate entity in exchange for favors rather than staying independently critical of its subject matter. Origin lies in one particular offshoot forum using tailgate in its URL that became known as the failgate.
Man, did you check out my new site?
No, it's clearly a failgate.