The official Gmail blog has announced that the Priority Inbox feature, which uses an algorithm to mark what it thinks are important emails in your inbox, is now available on the web version of Gmail for the iPhone. If you've set up the service to work on your usual browser, it'll now also work on Gmail for Mobile, which is up and running in HTML5 on iPhones everywhere.
I use Gmail almost exclusively for all of my email, yet aside from a short trial when it was first released, I've never really had much interest in Priority Inbox. I do a much better job of sorting my email than Google's algorithm, and I'm too worried that I'll miss something important that should have been prioritized if I depend on the formula.
But a feature is a feature, and since Gmail is free anyway, those of you who use Priority Inbox will probably be happy to see it the next time you log into Gmail from a mobile device.