The Gmail mobile webapp has been updated with new features. Most notable? Multiple sign-in and a couple of additions to the preferences panel.
On top of being able to quickly switch between accounts with a button on the bottom of your screen, you'll now be able to set a vacation auto-responder from your mobile device as well as a mobile-specific signature, to let people know that autocorrect is to blame for that disastrous spelling error and not you.
Introducing multiple sign-in and preferences on Gmail for mobile [The Official Gmail Blog]