What does the + symbol next to usernames mean?

[Railsplitter]

At the bottom of any given thread there is a list of members that are currently reading that thread.

What does it mean when a member's username is followed by a + symbol?

 

[Esav Benyamin]

I think that means they are on your friends list.

 

[Railsplitter]

I think that means they are on your friends list.

Thanks! That one went right over my head.

Thank you for your help.