Modules are the type of joomla extension which is used for page rendering. These are the small sections in joomla. These are totally depend upon the positions in joomla. Some of the jomsocial plugins are:

mod_activegroups: Displays the list of groups with most activities.

mod_activitystream: It displays jomsocial activities in any module position of your template.

Dating search: Dating search allows user to quickly and efficiently select the most basic information about users and quickly do the search against those fields.

Hello Me: It shows the most important information about the user in a convenient module box as well as allowing to be used as a login module for unregistered users.

JomSocial Connect: This module simply allows you to have a facebook connect button everywhere on the site.

Latest Discussion: This module will display latest discussion in the groups.

Latest Group Posts: With this module, administrators can show latest activity stream messages

Mod Notify: It allows users to see their notifications on every site page.

Photo Comments: It displays the latest comments on the photos.

Statistics: It shows various statistics of your site

Video Comments: It displays the latest comments on the videos.