Just having a whirl with WordPress’ P2 theme after hearing Matt Mullenweg wax lyrical. I like the look and it suits my kind of blogging – however – if you have many, many users in your system it WILL fall over.
Go to /wp-content/themes/p2/inc and open js.php
On line 250 wrap php comments around the code (or delete it entirely)
<?php /* var mentionData = user_suggestion() ); ?>; */ ?>
var mentionData = false;