Excellent Research Into Google's Indexation of Tweetshttp://www.stonetemple.com/how-does-google-index-tweets/
- from +Eric Enge
and the Stone Temple crew comes a great resource for those interested in how fast Google indexes tweets, what percent they keep in index (vs drop) and what predicts more/less indexation.
The only part I don't fully agree with are the conclusions. I think the researchers conflate indexation and discovery and assume that if Google doesn't index something, they must not be crawling it or finding URLs from it (which I'm not saying they always do - just that they could).