I've created a my own commenting system for my website using php/sql. It is very simple - the member's id and the comment id are recorded, along with the page id that they are commenting on. The comments are then pulled from the database for that page id (along with the user details) and displayed in ascending order.
This all works fine.
I'm after some advice as to any tips/tricks i can use with regards to stopping spam, ie multiple posts of the same thing (such as a 20 second gap between posts?) , stopping identical posts, and to filter things like swear words, links, etc.
I'm sure lots of you fine people have taken on this challenge before so if you could throw me even the smallest bits of advice from your experiences it would be very much appreciated.