[Question] that is plus sign

[nextgen22]

When viewing a thread you can go and see who else is but when I do it I sometimes see plus next to the name. Does any one know what this is for?

 

[Jellal Fernandes]

I see it too but it's no biggie...

 

[Darth Vader]

I wondered the same, haha.

 

[Vision]

If they are in your friends list you will see a + sign next to their name