This question already has an answer here:
When handling flags, sometimes I see one for, say, comments that will be obsolete, but aren't yet, or a post that's currently low-quality but I want to give the (new, otherwise-promising) user a little time to fix it before nuking it.1 What happens now is that I just skip past that flag and it continues to hang out in the flag list, cluttering the view, and I may have to skip past it a few times before I stop and ask myself "is it time yet?". Or sometimes I don't look -- I see that the flag count hasn't changed so I think the queue is down to the ones we're waiting on, but what I didn't notice is that someone else handled one of them and meanwhile a new flag came in that I ought to look at.
In cases like this I'd like to be able to defer the flag, to hit a virtual "snooze" button. While in this state the flag disappears from the flag list (perhaps there's a link to get pending ones so it's still findable), and then it comes back just like a new flag at the appointed time. I don't think we need to be able to vary the snooze time; that might be nice, but a simple "ask again tomorrow" would do the trick on the smaller sites where I see flags. (SO might need a different value.)
1 This may seem silly on large, established sites with tons of users coming through, but on smaller betas there can be more of a call to nurture new users.