Just three days after Time Warner Cable signed on to offer HBO Go to its customers, Cablevision has also agreed to start supporting the popular service as well. Cablevision was one of the few that didn't already offer HBO Go, likely because it has its own apps it wants to promote to subscribers. But once Time Warner came onboard, Cablevision — which serves mostly the New York area, and competes directly with Time Warner — joined in as well. The agreement gives Cablevision's HBO subscribers access to back catalogs of all of the network's shows and movies, from anywhere, through HBO Go's apps for PC, iOS, Android, and Roku, with support for Xbox and other devices coming soon. It also includes MAX Go and its stable of Cinemax content, and will be made available to customers "in the next few months." With Time Warner and Cablevision on the list, nearly all of the major American cable companies now support HBO Go, which means the arms race with Netflix might be getting a little more serious.