Adam's answer is spot on, and I'd just like to augment it a little.

For **questions**: there's closing. Or rather, putting on hold. That's the method we have to send a signal that "this post isn't currently up to scratch, but it can be made good". However, I think that when closing, it's *incredibly* important that we have a comment left along those lines: that while this may *currently* not be OK for us, it can be, and the "hold" is temporary.

For **answers**, we don't have anything quite like closing. However, it is still important - as Adam says - that answers are given a chance to improve. Unless answers are *really obviously* bad (spam, irrelevant, should be a comment, etc), we should comment and leave a while for edits. If they don't happen, then deletion is the way to go.

And a request, from me to everyone - **please please please** flag stuff. On questions, if they're not up to scratch, flag for closure (*not* VLQ, because that sends it to the Low Quality queue, whereas a close flag sends it to the close queue, which is where it should be). On answers, if they're not up to scratch, comment, flag as VLQ, and we'll come along and take a look, comment, and mark it for review a few days later.