It only works for users who already subscribe to CNN via AT&T, Comcast, Cox, DISH Network, Suddenlink and Verizon. Time Warner Cable is the notable, ironic exception, mostly because CNN is owned by Time Warner -- a company that once was the parent of Time Warner Cable. The two are related only in name at this point.
In addition to streaming CNN and Headline News, CNN will also offer up to 4 other streams of breaking news and events. Today, CNN was streaming live coverage of the US Senate, and video of the Atlanta and New York City skylines.