The mobile skin should have a box to type a status update. It would be perfect, my users could just type into their phones about what they're doing.

I agree. I bought a new mobile phone last week with wifi and 3G and was surprised I couldn't update my status while I was away for the weekend.

3DKiwi

The iPhone application itself has this functionality, as will the Android app once it's released. As for building it into the skin, that's tricky. There's duplication of functionality for the real applications in that situation.

While I don't really think status update in the mobile skin is necessary, not doing it because it's in the mobile app isn't really the best reason IMO. I imagine a significantly less portion of mobile users will be using the app compared to those who access it via their mobile browser.

It's a fair point, but it's just something to consider.