The Top users module allows you to display a list of the 'top users' in a specific channel/network or across all networks.
The aim of this module is to foster discovery of interesting and relevant people to your users. The default criterion is the top publishers- users who publish the most content. You may choose to display other criteria: the top contributors, and the users who have the most friends.  
Settings
Thumbnails size – choose the size you wish to display the users profile photos.
Link user profile URLs – choose to link directly to the user profile page, rather than the mini profile (light box) that usually appears when clicking on a user's photo or username.
Hide users' username – tick if you do not wish to display the username next to each user profile photo.
Users per page – choose how many users to display in every page, to view more there will be a 'Next' button.
Hide paging controls – hide the paging options and 'Next' button, and display only one page of results of the top networks with no options to view more results.  
Show sort options – allow users to view the Top users based on other criteria - the top contributors (in the last seven days), or users with the largest number of friends.
Allow replication – allow other users to replicate this module and display the top networks on their network.
Select channel – select a channel to display the top networks from (the channel the current network belongs to, or all networks across channels).