It's an arms race, and the anti-ad people will win, because they have greater numbers among the programmers with extra time on their hands.
I think what it boils down to is this: the more annoying the ads on your site, the more people will either block them or avoid the site. Going to block the extension or the browser? Unless you've got content that people must absolutely have
, plan to see your traffic drop drastically.
While there is an extension to avoid Google text ads, I don't think it's nearly as utilized as the add-ons to avoid graphic ads that are, more often that not, both annoying and bandwidth hogs for those on dial-up (not many, but they're still there).
Let me put it this way-- would you rather have someone come up to you at a convention and casually ask if you'd like a brochure about something related to the meeting, or someone start screaming in your face about an offer totally unrelated to where you are?
Calm, but well-marked, related ads are, I think, where the money is. Google isn't hurting for cash these days, are they?