It appears that every time I post, it tells me flood control is on, and that I must wait 10 seconds before retrying. The second try always works in my experince, but I look and their are 2 posts by me, both identical to what I had just written, so I usually delete one.

Anyone else been having shit like this happen with flood control? And exactly what is its purpose if it doesn't work?

Somtimes it happens to me too. But it's rarely now, altough some months ago it happened to me all the time.