[josefresco]

They key difference I think is that Google accounts or gmail accounts were not used as the hub of social interaction (like Facebook) when Google launched Buzz. All the hipsters had built these huge networks on Twitter and Facebook already and now suddenly had to re-assemble a social network from scratch based on their GMail address.

If history was different and everyone used their Gmail account as their social identity, things would have been different as Twitter would have just been a 'feeder' service like 4sq/Go are now.

[Shakattack]

That's a good point. But I also wouldn't call Facebook my all encompassing social identity. I don't update my status with everything I tweet; I don't even sync up Foursquare and Facebook because I don't want everyone on Facebook knowing where I've checked in (and I don't think I'm alone because 20% of Foursquare users sync up with Facebook). Many people just find it annoying, but the bigger reason is that I'm not really that 'close' with all my Facebook Friends. If I post a check-in to facebook, I'd only want a fraction of the people to know.

I haven't gotten the rollout yet but hopefully Facebook realizes this and makes Places something you can use with some of your friends, and not all of them.