It took a couple more months than originally expected but Gaikai's game streaming service is finally set to open its digital doors today. The new service resembles OnLive in that it will run games on remote servers and stream video back to the player through a browser plug-in, without additional downloads or special hardware required. This means that even the most-demanding of games can be played on low-end PCs, but beyond the technological aspect of streaming games though a broadband connection, the two companies actually have a different business plan in mind.

Gaikai is limited to game demos – at least for now – and is pitching itself as a game advertising company to attract developers. In a nutshell, the idea is to reduce the friction that stops players from making impulse purchases on the web, allowing them to actually try games for free at the point-of-sale and then pay for a full download of the game, order a physical copy, or simply share the game demo on social networks so others can try it.

At launch, demo versions of EA titles Mass Effect 2, Spore, The Sims 3 and Dead Space 2 will be available – the latter of which requires you to fill out this survey first. After a short test determines if your connection is suitably fast for streaming, each demo will launch in a Java window with limited options to edit the game settings. I fired up Dead Space 2 for a quick 10-minute run and was gladly surprised to see that the game ran at decent (not great) frame rates, with graphics comparable to that of a modern game console, and that the demo wasn't region-locked to the U.S.

It remains to be seen if more publishers decide to join the platform and if full-scale games ever make the lineup. For now, Gaikai CEO Dave Perry says its company will demo stereoscopic 3D streaming on Battlefield Bad Company 2 and other titles running within Facebook this week at the Game Developers Conference in San Francisco.