One of the benefits of Xbox Live is the ability to always be online. With the exception of a few companies who demanded their own servers (EA specifically), all Xbox Live games remain online and running.
As of April 15th, that is no longer the case.
That’s right folks, as of April 15th, 2010, all Xbox 1 games die. This includes Halo 2, Counter Strike, Crimson Skies, Splinter Cell, MechAssault, and everything else. They cannot connect via the Xbox 360 either in when in backwards compatibility.
This decision takes away one of the best things about Xbox Live, knowing that you can always hop in for a quick game of Halo 2 if you were bored, or enjoy Counter Strike on a console instead of the PC. Now those days are gone, despite the peer-to-peer nature of the hosting. Microsoft’s official announcement talks about the difficulty of the decisions, and stating the reason behind the decision has to do with limitations of the service set up because of Xbox 1 compatibility (friends list cap?).
Keep in mind, that Microsoft also just recently stopped selling Xbox originals for digital download, which have also now lost their online support.