The sale of .mobi web domains has started to allow companies to build web pages that easily work on mobile devices, including phones and personal digital assistants (PDAs).
Internet regulatory body ICANN approved the .mobi domain last year, but businesses had not been able to buy one until this week.
Registrations of the new domain are being sold off in stages, with mobile operators, leading portal players and other industry players being given the first chance to buy a .mobi domain.
From mid-June, trademark holders will then be given the chance to register for the domain. In August, anyone will be able to buy one.
The same registration process was used by the registrars responsible for awarding the new .eu top level domain.
The process is designed to stop domain name dealers from hijacking brands and then demanding large sell-on fees to trademark holders.
A .mobi domain will be used to encourage users to visit certain websites, which are designed to be viewed using small screens on devices connected to slower mobile networks.
Companies can apply to domain registry company mTLD to get a .mobi domain.