14. A search engine method comprising: receiving, by a computer, a user query from a user of a search engine; providing, by the computer, a task query and contextual information to a task server, the task query and the contextual information based at least in part on the user query; receiving, by the computer, data representing a task from the task server, the task being an action relevant to the user of the search engine, the task including a semantic solution that comprises mappings between slots of the task and tokens in the user query the tokens including at least an annotation token and a subject token, the slots including a given slot, the semantic solution comprising a mapping between the subject token and the given slot when the annotation token indicates that the subject token is likely relevant to the given slot, each of the slots defining a parameter of the task into which one or more tokens in user queries can be filled; providing, by the computer, the task to advertisers; receiving, by the computer, bids on the task from at least some of the advertisers; and providing, by the computer, a page to the user as a response to the user query, the page containing search results and an advertisement, the search results responsive to the user query, the advertisement associated with a successful one of the bids.
15. The method of claim 14 , further comprising: after receiving the bids, retrieving, by the computer, information regarding the advertisement from one of the advertisers.