Abhinav Singh has a new post today looking at his method for preventing duplicate comments (similar to a method used on Wordpress blogs) using memcached.

In this blog post, I will put up some sample PHP code for Duplicate comment detection using Memcached without touching the databases. Towards the end, I will also discuss how the script can be modified for usage in any environment including forums and social networking websites.

His method uses a custom function (is_repetitive_comment) to create an md5 hash of the comment and username to check against the stored values on the memcached server. Code is included as is an explaination of how it all works together.