.mobi is a top-level domain approved by ICANN as a sponsored TLD. It will be restricted to mobile devices and sites providing services for them on the Mobile Web. It is sponsored by a consortium of companies including Google, Microsoft, Vodafone, Samsung, Ericsson and Nokia. As of November 2005, the domain had been added to the global internet root and was getting ready for its opening. Starting May 22, 2006 industry members can register a .mobi domain name, June 12 for trademark holders, and Aug. 28 general registration.
Since many of the mobile devices which may use services under this domain are telephones, there is some overlap between the target market of this and the .tel domain, also approved by ICANN in the same round.
Responding to the early criticism, .mobi engaged with the W3C Mobile Web Initiative (MWI) and took a leading role in formulating the MWI Best Practices for mobile content. The practices outlined a number of ways to achieve good user experiences on mobile Web-enabled devices, and recognised several methods of implementing these practices. The .mobi "Switch On!" guidelines are derived from the W3C Best Practices.
The methods of achieving these Best Practices are used today by major providers of mobile content, including mTLD company's own website mtld.mobi. Their site redirects some clients to pc.mtld.mobi site, which is intended for fixed-Web clients and is unsuitable for mobile browsers.
There is a significant community of users who seek a more consistent and predictable experience when they use their mobile device to access internet content. They claim that .mobi will help the user by requiring that .mobi sites will render acceptably on a mobile device, preventing waste of the user's battery life or data transfer quota. There are technical solutions that provide this today: compressing/downsampling proxy servers and microbrowsers, like Opera Mobile and Opera Mini which can tailor any website to small display (using Small Screen Rendering technique). There are also specialised content adaptation solutions that mostly operate on the server, where they employ specialised adaptable authoring technologies. The .mobi organisation does not itself mandate any particular technology, but does insist that .mobi sites will produce user experiences consistent with their guidelines.
Additionally, some have pointed out that "mobi" is an unfortunate choice for mobile phone text entry interfaces, requiring nine keystrokes in many common setups, compared to seven for "com".
The .mobi domain name's application was strongly endorsed by its registry service provider, Afilias, which was able to make a case to the evaluators of ICANN that it would operate the registry in a stable and secure manner, without resorting to special tricks in the DNS.