1. A method comprising: determining, at a server, a plurality of values for a keyword of a web page; receiving, from a user computer at the server, a request for identification of keywords of the web page, the request comprising data associated with the user computer; determining, at the server, a location of the user computer and a local time at the user computer based on the data associated with the user computer; selecting, at the server, a value from among the plurality of values for the keyword that corresponds to the location of the user computer and the local time at the user computer; determining, at the server, that the value meets a criterion; responsive to determining that the value meets the criterion, selecting, at the server, the keyword; determining, at the server, keyword identifying information based on the value and the keyword; and transmitting, from the server to the user computer, the keyword identifying information.