Search for every tweet

Social search engine Topsy's search index now includes every tweet.

Researchers and others will now be able to search every tweet, dating back to Twitter’s launch in 2006.  Topsy has stated that its search database contains over 475 billion tweets, images and other data elements. 

The archive and search facility are freely available – Topsy Pro (a paid for service) offers more advanced analytics tools.

More on this from Mashable.