I used to have the problem of posts disappearing (which is more due to my internet connection than the forums). Now I automatically Cmd + A, Cmd + C before posting. Took a couple of days to get used to, but now it's pretty reflexive, and take about the same time as typing two extra capital letters. Sure isn't as good as everything actually working properly, but if you are having lots of trouble with long posts being kidnapped by the server, it's a decent safeguard.