I don't understand Google a lot of the time. They have plenty of assets and perhaps less talent than raw financial influence? It seems the amount of lazily put together sites by Google is always growing. With their assets I'd be inclined to think there is no excuse for them failing to dominate a market unless their intention is merely to get a percentage of market share.
So the question I would ask is: does Google want to dominate the market or get a percentage of it? I mean even if just IM people go and spam one another, it's more money for Google.
Google is doing "everything" these days. I think it's partially a tactic on their part in that competitors can't tell if they are making a serious product or not.