The graph shows it currently as being at 5%.

I really doubt any browser will start installing it by default, so I think adblock will be limited to: a) Really technical people (HNers) b) Friends of HNers that are bothered enough by the real web experience while on their friend's systems that they go ahead and install adblockers.

I don't see adblockers covering more than 10% of web users, and they're likely the least valuable 10% of web users (they may earn a lot, but they don't have burning holes in their pockets either).