I recently tried out the StackExchange android app. I like it quite a bit. One thing that bugs me though is the lack of a way to watch a question for the duration of your session. This isn't a problem on a computer. I'll see an interesting question with no answers, so I just open the question in a new tab. And then I'll keep browsing the front page and come back later to the tab I opened and refresh and read the answers that were posted to the question.
On the android app, this ability is quite lacking. The best thing I can do is open the question in my browser and go to my browser later.. which kind of defeats the purpose of using the app in the first place.