No post count for short posts (with under # characters)

[modtang]

How hard would it be to write a mod to do this?

Basically I want to stop users who spam with one word replies or just a couple of smileys from having that post count towards their total post count.

There's a mod for IPB that does what I'm talking about: http://mods.invisionize.com/db/index.php/f/4265

If anyone could help me write this I'd be much appreciative. Thanks.