I'm not sure if either I'm not understanding the complete function of count or if it is busted. What I try is to check to see if there are more than 1 player on the server or in the case of an area. I couldn't get this to work properly when checking an area

 testfor @a[x=72,7=64,z=80,r=3,c=2]

so I tested it for all on the server.

If I have it set to testfor count=2

 testfor @a[c=2] 

when I'm the only player on, the comparator still outputs a signal. I would expect this to NOT send out a signal as the players on is 1, not 2.