A client asked me about .mobi, so here is a brief introduction.
The .mobi is a top-level domain and was first introduced in 2005; however it has only recently been available for registration. It has been sponsored by companies including Google, Microsoft, Nokia and a number of other phone manufacturers. Its intended use is for sites which have been created specifically for mobile device use, and as such any site created must conform to the ‘mobile-compatibility style guidelines’ which are derived from the W3C Best Practices; this will be enforced via challenge, rather than initial sign-off.
It is worth noting that any current domain can serve content in a format compatible with a mobile device, however, the .mobi domain is seen as a guarantee for the user that the site will work and avoid high levels of data download which is a cost against a users data quota and also a drain on battery life of the device. The guarantee comes about through meeting the standards and designing with the device in mind, rather than any technological intervention.
What needs to be done to make the new site .mobi compatible?
The are a set of guidelines, these must be followed in order to avoid challenge to any .mobi site deployment. Also a specific set of mobile content would likley be created and managed to serve mobile devices.