The .mobi domain is designed to clearly identify internet sites and applications that have been made for mobile devices.
This news makes sense in the wake of news coming from Google this morning that they are providing Google News for phones. For now you can access it by going to
http://news.google.mobi/news?output=xhtml on your phone browser according to the announcement, but this is just the first step towards google.mobi being the destination for mobile information.
The company also announced that they are working with Sony Ericsson to provide phone-sized versions of Google Web Search and Blogger. Google is obviously positioning themselves to continue to be at the forefront of whatever comes from this new domain.