Agent for identifying domains with content arranged for display by a mobile device

A system, apparatus, and method are disclosed for providing a single source for searchable content by mobile devices. Mobile user agents crawl host sites to determine whether there is content that may be viewed by any of the mobile user agents. If files are identified as viewable for a given mobile user agent, the site is tagged as crawlable. A best mobile user agent may also be identified for that site, based on number of files viewable, response time, file mobileness, or the like. The sites may be discovered by instrumentation of URLs with mobile device keywords, performing a backlink analysis to discover interlinking of mobile device related sites, exploring URLs of a known host name for potential starting points for mobile device sites, or employing a list of known popular conventional sites with a mobile user agent for possible redirections to a potential mobile device web site.