Is this The Guardian's answer to Siri? @GuardianTagBot, is Twitter-based search assistant which allows you to tweet a question about anything in the paper's content.
Tagbot will reply if you tweet it with a search term on your phone or online, sending you a link to the latest relevant Guardian coverage that best matches what you were looking for. For example, if you tweet '@GuardianTagBot latest baseball news?', TagBot will match the words 'news' and 'baseball' against the content the Guardian has stored and tagged on its API, and reply with the most up to date content.
The service is still in beta, so The Guardian is asking for user feedback; at the bottom of the link list page that the tagbot sends back, you are asked to rate if it's been a "goodtagbot" or "badtagbot."