The difference between Google and Facebook (okay, a difference) is that one launches rival, separate services, the other adds features to one huge monolithic service. So Google will never match Facebook, because while they have good calendar systems, great messaging systems, a good IM service, a fairly terrible Photos service, I-have-no-idea-how-good set of tools for small businesses to create sites for themselves, a nascent social gaming platform etc etc, each has only a subset of Google users on them. With Facebook, all this stuff is shoved in your face, and it all depends upon you being within Facebook. Variously fiddly privacy settings notwithstanding.

In fact, thinking on it, Project Titan is something of a departure for Facebook. Here's a big new tool, and it's aimed at communicating with ... people not on Facebook. I can't think of a time they've done that before. I wonder how it'll feel.