Look to be honest..I don't thinkTwitter is that important tool for site optimization or even getting any kind of traffic. Still i don't know Google has opted to get all tweets indexed in its search engine.
I think this will let increase the spamming and is not anything for anyone.
Yeah, I finally "understood" Twitter after an earthquake near us. Real people on the ground can get out the word quick about a specific topic without a website, and post links to real information - quickly. In nations where the gov't is out of control its a great tool for organizers, protesters, etc... I finally "like" twitter - I just don't think its a marketing tool. (we just want it to be!)though I do realise and appriciate the importance.
I am a bit disappointed with the services of Google and twitter. Though it proves to be of a good value, but often it is seen as a huge spam tool.