pull down to refresh

Or even more than that, because if you click through it when you sign up, you never look at it again (unless you read a thread like this :) ).
If I had to suggest something, it'd be - two buttons next to each post, or something that looks a bit like reddit's 'gold' and other awards, but it's an actual button right there. I suspect other stuff (including long press) is just not going to get people using it.