If you use AdBlock Plus to keep your Web browsing experiencing free of annoying clutter, this is the kind of tweet that might grab your attention: “Google paid AdBlock Plus to get its ads whitelisted.” Millions of people use AdBlock Plus. Per Wikipedia, AdBlock Plus is the single most popular extension of any kinde for Firefox. But I’m betting that a hefty percentage of those millions don’t realize that major advertisers, including Google, can pay to have some of their ads “whitelisted” — in essence, given a free pass through AdBlock Plus. The so-called “Acceptable Ads” feature is turned on by default, meaning that users have to specifically opt-out if they don’t want to see such ads. There seems to be no doubt that AdBlock is generating some sort of revenue stream from the practice.