[Lynne]

It's just php. You can look into a php function that generates a random number between x and y and apply it.

PHP Code:

$forum['browsers'] = rand(1,50) + $forum['browsers'];
$show['browsers'] = ($vbulletin->options['displayloggedin'] AND !$forum['link'] AND $forum['browsers'] ? true : false); 


That's just a simple one. You can modify to suit your needs and make it look more realistic.