6. A message classification system for identifying messages on a social networking messaging service, comprising: a message server configured to store search queries; a message database configured to store received messages; and wherein the message server is configured to: receive a search query, where the search query comprises at least one search query term; calculate a plurality of query scores for the search query with respect to a plurality of categories using the message classification system, where: each of the plurality of query scores is a score determined with respect to one of the plurality of categories; a predetermined plurality of keywords is related to each of the plurality of categories; a normalized keyword frequency is assigned to each of the predetermined plurality of keywords related to each of the plurality of categories, where the normalized keyword frequency is determined for a given predetermined keyword from the predetermined plurality of keywords based upon the frequency with which the given predetermined keyword appears within a predetermined training data set comprising a plurality of messages that are relevant to the category to which the given predetermined keyword is related; and wherein the message server is configured to a given query score from the plurality of query scores for the search query with respect to a given category from the plurality of categories using the normalized frequencies of the predetermined plurality of keywords related to the given category to determine a likelihood that the at least one search query term is present in a message relevant to the given category; identify at least one category relevant to the search query based on the plurality of stored one query scores using the message classification system; retrieve and score messages from a social messaging service based upon the search query and the identified at least one category relevant to the search query, where the message server is configured to messages with respect to the search query and a particular category from the identified at least one category identified as being relevant to the search query by: performing a plurality of parallel searches that retrieve messages from a social networking messaging service that match the search query and iterative combinations of the search query and at least one of the predetermined plurality of keywords related to the particular category to retrieve messages likely to be relevant to the particular category; scoring the retrieved messages with respect to the search query and the particular category by configuring the message server to: calculate a sum using the normalized frequencies of the predetermined plurality of keywords related to the particular category, where the sum is determined based at least in part upon the normalized frequencies of the predetermined plurality of keywords related to the particular category present in the retrieved message; calculate a ratio of search query terms in the retrieved message to the total number of search query terms; and score the retrieved messages based upon the calculated sum and the calculated ratio; and return at least one of the retrieved messages as the search result based at least in part on the retrieved message scores.
10. The system of claim 6 , wherein the server is configured to score the retrieved messages with respect to the particular category identified as being relevant to the search query by weighting the retrieved messages based upon the amount of time that has elapsed since the retrieved message was posted on the social networking messaging service.