tedster - 4:16 pm on Sep 17, 2011 (gmt 0)
I've seen this kind of result, too - but only recently. It surprised me because of all the Twitter results when we know that Google did not renew their deal with Twitter. Even when they had the Twitter Firehose, the Twitter results were not done to this extreme.
I think it's a test of some new idea - and no, for the search where I saw it, I did not find all those tweets useful.