The service is also blocked by those providers if accessed through Roku players.
Samsung has announced the availability of the HBO go streaming service on its internet connected TVs, letting HBO subscribers check out all their favorite content streaming whenever they want. Most, but not all Samsung TVs can handle the app, but Samsung was not specific as to which cannot.
Don't get too excited if you're a Comcast or Time Warner subscriber though. You'll find the app blocked. Both companies have disallowed HBO Go on connected TVs and devices like the Roku Player as well. The reasoning behind this decision is unclear, and neither company has had much to say on the issue, but we're gonna go out on a limit and guess it's a matter of $$$$...$!
A representative from Comcast was quick to point out that you can get all the HBO Go content via the Xfinity TV app, though that doesn't do much good for Samsung subscribers without Xfinity.
Source: Multichannel News