I find it hard to find any explanation for this behaviour that fits except for the rather bleak suspicion that right now all that matters is gaining market share and locking people into your walled garden. Perhaps they are getting some return on investment now by creating ever more detailed advertising profiles on their users, but that doesn't seem sustainable — it strikes me as rather bubblish.

I wonder what the long term vision is. More data harvesting for advertising? Become the de facto platform for services offered through your chat network? The latter reminds of how every company needed a presence in Second Life to engage with customers and leads…