Very true, but the network Google is looking to expand is Google+. The point of having a more competitive IM system is not to build a IM network, but to bring t

Very true, but the network Google is looking to expand is Google+. The point of having a more competitive IM system is not to build a IM network, but to bring their IM users into the Google+ network. Therefore, a proprietary solution where users are forced to use Google's service is a feature. Disallowing third-party clients can even be spun into a move towards openness: since the ultimate goal is to have everything on the open web, the main interface should be the one on Google's website; native clients are a necessary less-open evil on current mobile platforms, not something third parties should waste time on.