The mail and browser systems had to be recreated from scratch. I've been the only person working on it, and only when more important stuff wasn't going on, so naturally it's not being done very quickly.
Nevertheless, the new community (browser and mail) systems are nearly done. The server side has been operational since last fall (which is how a handful of players have yellow clan tags in game), and the only remaining work has been on building new user interface components for the in-game UIs (since the old ones are not compatible with the new server).
Currently, the in-game mail UI is functional, and browser UI is about 70% done. I expect about 16 hours more work required to finish it off. You can track development progress in the roadmap thread: http://www.tribesnext.com/forum/index.php/topic,508.0.html
I'm wrapping up the active development on Tribes 2 and putting out a final patch sometime in the month of April.