"AdSense, in my opinion, is the worst thing to happen to the Internet," says John Scott, who runs the V7n.com online forum for search marketers. "Google is ... in essence, paying people to inundate the Web with literally billions of worthless pages." Whatever its editorial worth, the AdSense business model clearly works for what blogger Jennifer Slegg describes as "hundreds of thousands" of website and blog publishers. Slegg, who runs the JenSense AdSense tips blog, says the monthly AdSense bounty ranges from $100 to tens of thousands of dollars. "The average is more like a few thousand a month," she says. "The ones who do really, really well, however, really work for it. It's not a windfall; they put in the hours." (Source)
You don't criticize a thing when people implement it wrong. A knife could be used for killing ,so should we stop using and buying knives??!! Adsense and Adwords did benefit to a lot of people and is a good advertising way. Ask advertisers about that who everyday bid for new words and didn't quit adwords. However, low quality sites and MFA's are a problem and google should do something about them.
Adsense (and the other ad systems) make it easy for smaller information providers to earn from their sites without charging for access. Without advertising we would see more subscription based sites and perhaps less free or opensource information. Sure, we'd lose the garbage but we'd be cutting off our noses to spite our faces. You could make the comparison of "free to air TV" and "pay TV". Where I come from there isn't a quality difference, not really. But with one you pay be watching ads (or reaching for the remote), with the other it hits you straight in the back pocket. Is free to air the worst thing that ever happened in TV. No, I don't think so. I reckon the analogy holds.
I agree to an extent, there are a lot of completely worthless MFA sites that proliferate the web at the moment and it's probably going to get worse as the site owners simply 'fire and forget' and go off and create more. Again, you can't really blame AdSense, if you look at it the other way it encourages people to create more useful informational sites that may have been hard to monetise before.
I think the quote from the article has some truth to it. Adsense has helped create a ton of worthless sites, but it's also helped bring about quite a few useful sites. Without Adsense, there would be noticeably fewer sites on the Web, but those sites would probably contain better, more useful content written by people who are passionate about their topic and not just in it for the money.
Nobody can deny that adsense has given people an incentive to create web pages for profit and as a result, alot of pretty useless pages will pop up everywhere. Its up to the search engines to get smarter and make sure the good pages get the traffic.