This makes a great deal of sense for a network like hi5, that has a large international user base, which translates into a need for ready mobile access, as many other countries use their mobile phones more often than a PC.
So what can you do on hi5's new mobile network? Send messages, update your status, share photos, and add new friends, to name a few features. As far as media-sharing goes, users are pretty well covered, though I'm interested in seeing how networks will continue to push the boundaries in regards to third-party applications and advertising therein. As hi5 already supports OpenSocial, and has just announced its added support for Widgetbox's OpenSocial applications, it's clear that hi5 is ready to offer more options to both its developer community and user base at large.