1. A method for determining related search terms for a landing page on a domain, using one or more computers, the method comprising: receiving, by the one or more computers, a request for related search terms for a domain; determining, using the one or more computers, an initial pool of related search terms for the domain; obtaining click data on the domain, using the one or more computers, for the initial pool of related search terms determined for the domain; obtaining revenue generation data for each of a plurality of the initial pool of related search terms, using the one or more computers, wherein revenue generation data comprises data indicating that a user has clicked on a given one of the initial related search terms present on the domain and further clicked on an advertisement displayed in response to clicking the initial related search term; determining, using the one or more computers, a first set of search terms from the initial pool of related search terms, the first set comprising search terms with higher revenue or click generation as compared to other search terms of the initial pool of related search terms, based at least in part on the obtained revenue generation data or obtained click data; generating a second set of at least two new related search terms, using the one or more computers, comprising: obtaining keywords, using the one or more computers, that are semantically relevant to the first set of search terms based at least in part on one or more match scores; obtaining for each of multiple of the keywords, using the one or more computers, how many advertisements are targeted to the respective keyword; obtaining for each of multiple of the respective keywords, using the one or more computers, an amount that advertisers have paid over a period of time for use of the respective keyword by the advertisement server to bring up their respective advertisement when a direct search is made using the respective keyword; selecting respective keywords for the second set of new related search terms based at least in part on how many advertisements are targeted to the respective keyword and based at least in part on how much advertisers have paid over a period of time for use of the respective keyword; and listing, using the one or more computers, on an updated landing page returned for the domain, the first set of initial related search terms with higher revenue generation and the second set of new related search terms.