After reading this answer, scroll to the bottom of the page and you will see the words "Who's online".  Below that heading you will see how many registered users and guests are online at that very moment.  Registered users will have their username displayed in red.  You can visit that member's page by clicking on their name.

Some of our members use something other than their first and last name as a username, which will prohibit you from knowing who they really are unless you visit their personal page through the Search JEN Members tab located in the right side bar of this screen.