Sifter provides search and retrieve access to every undeleted Tweet in the history of Twitter. Users submit historical Twitter estimate requests using a variety of using a variety of Twitter Premium PowerTrack rules. When the query is done, Sifter generates an email estimating the approximate number of tweets responsive to the query and the cost to get the data. If you make a purchase via Sifter, the data is licensed by Texifter. They store the Twitter data in a free trial Enterprise DiscoverText account where you can perform advanced text analytics to search, filter, cluster, code, and machine classify the data.