It's been less than two years since HBO's owner Time Warner and Time Warner Cable were closely corporately related -- as well as AOL, Engadget's owner -- and one might think that ties remain. Those thoughts should be quickly dashed, once again, now that we know TWC's beta of HBO Go finally started this week. The limited trial for SignatureHome customers will be further restricted to computer based clients, but is expected to be short. It would have to be pretty darn short, though, to keep Time Warner Cable's December promise to launch "in the next month." This really makes us wonder how hard