It can make the thread table bigger depending on how many users view how many threads. Nonetheless, I'll write it ;)

make sure you put a disclaimer on it... reminds me of cigarettes ;)

Alright, but still, it would make the table huge if the forum is very big:p

i think it could be done with a seperate table, then you can reduce the users where can use this option (e.g. admins,mods or usergroups) then i think it's not the problem, or is it?

userid | threadid | timestamp

i think this is all, or?

Released. Yes, a separate table might have been better, but it's still going to add performance and size problems. The one I just released uses three queries maximum but tries to save them when possible.

wouldn't it have been easier and less queries if you just created a column with the username and not the userid so you won't have to make another query to fetch the username of the userid?

hope that makes sense ;)

No, because usernames can change.