What is your rep power?
You're rep power is how powerful your rep is.
Say if you had 15 rep power, then when you would +rep someone you would give that much rep.
You're -rep power on the other hand is you're rep power divided by 2.
say if you had 15 again you would give away -7 rep becuase it is rounded to the lowest if it is an odd number
to check your rep power, it will say it under your avatar where it shows your rep bars