[CentOS] odd popups

Occasionally and without any action on my part, I get a popup
saying I need to authenticate in order to read others' actions.
I have no clue what this is for, so I always reject them.
Anyone got a clue?

Image attached.

-- 
---- Fred Smith -- fredex at fcshome.stoneham.ma.us -----------------------------
               But God demonstrates his own love for us in this: 
                         While we were still sinners, 
                              Christ died for us.
------------------------------- Romans 5:8 (niv) ------------------------------