A lot of the proposed solutions here seem pretty complicated. The one that makes the most sense to me, while definitely not perfect, is to start by limiting new

A lot of the proposed solutions here seem pretty complicated. The one that makes the most sense to me, while definitely not perfect, is to start by limiting new posts to accounts that have existed for a certain interval (maybe even just 30 minutes). That should filter quite a bit of spam and even though it's still easy to get around, at least it will require more effort. It's also very easy to implement. Then you can experiment with other methods, but I doubt we'd miss many meaningful posts with this kind of limitation. The other bucket of accounts created for spamming would need a little more sophistication, like maybe a queue limit per day. Still not too crazy.