Ad's are simple to bypass. If one uses an ad script or program such as Ad Sense then the FF blocker, and similar will normally block them. But, if one hard codes a simple image with a linked url into the main file such as SMF's index.template then the ad's normally can not be blocked.
As far as harming the webmaster in terms of revenue? I think that if a webmaster was concerned about revenue then they would make sure to offer ad space that is accessible in all browsers regardless of any blocking software or program.
Hard code and forget about pre-made scripts is the only way to go to ensure that your ad space buyers will be guaranteed accessibility to all audiences regardless of browser settings.
Personally I would not offer my ad purchasing customers anything but hard coded space.
Yes, I completely agree on this. But getting an advertiser is really pain in ass.
And continuing the term too is difficult. I managed to find one advertiser for my site but it lasted only for a month. the ad slot was of 300x250 and the advertiser requested me to use a tracking script with it.
After a month I got no response from the advertiser....maybe he didnt get the expected members to his forum via the ads published.
So, until we manage to find the long term advertisers, we are forced to use Google ads for the revenue generation.