12. A system comprising: a posting web interface to receive a posting to a forum, the posting requesting a response; a keyword extraction module to extract a keyword from the posting; and a processor of a machine configured by a posting assignment module to: retrieve a responder identifier by executing a first query with the extracted keyword as a retrieval argument of the first query, the responder identifier corresponding to a person available to provide the response; obtain a count of keywords by executing a second query with the responder identifier as a retrieval argument of the second query, the count of keywords quantifying a number of times the keyword is included in responses provided by the person available to provide the response; identify the person as a responder to respond to the posting based on the count of keywords; and assign the posting to the identified person to provide the response.
12. A system comprising: a posting web interface to receive a posting to a forum, the posting requesting a response; a keyword extraction module to extract a keyword from the posting; and a processor of a machine configured by a posting assignment module to: retrieve a responder identifier by executing a first query with the extracted keyword as a retrieval argument of the first query, the responder identifier corresponding to a person available to provide the response; obtain a count of keywords by executing a second query with the responder identifier as a retrieval argument of the second query, the count of keywords quantifying a number of times the keyword is included in responses provided by the person available to provide the response; identify the person as a responder to respond to the posting based on the count of keywords; and assign the posting to the identified person to provide the response. 14. The system of claim 12 , wherein the posting assignment module is to identify the person as the responder based on the count of keywords being highest among a plurality of counts of keywords corresponding to a plurality of responder identifiers corresponding to a plurality of persons.