Fox is joining the ranks of other media conglomerates like ABC and NBC in offering TV shows online. Partnering with Apple, Fox wants to make their shows available for free. There's a significant difference in the lineup Fox will offer compared to NBC and ABC, however, as they will not be offering their most popular shows like Family Guy.
Instead, they are offering newer shows they feel need more promotion or aren't getting as much view time as they'd hoped. Their aim is to make the shows more widely available, which might increase the audience. That's probably a smart move, particularly since these will be available without having to watch through commercials. In the future, they are probably planning to make it a paid service - but at least they are giving online access a shot.