I gave turfsniffer what I thought was a green rep. He told me that it was grey by returning the rep. His rep was blue. Looking at our post counts and reputation, I would think that we would be giving each other green rep. No idea whether either rep gave points or not, I just don't pay that close of attention to it myself. I am curious though - I thought Blue rep was for newbies and it didn't count towards you or against you. I can't recall ever seeing grey rep before or reading about it. Last I remember, it was all green and red - except for newbies that was blue.
Rep is general chat/P&R/Introductions is grey (does not count that is), unless the member who gave you green has power of altering other members rep more than 10, in that case its green and gives you one point.
1 by 10th actually, and Shawn uses round to lowest function, that means if you have total rep pwer of 18 it would be 1.8 in the GC and will be rounded of to 1. but if you have total rep power of 20 then it would be 2.* *Not sure about it, but my observation and Porgrammer's logic suggests me this.