I think a significant amount of the awfulness (warning: bad language, possibility of blinding reflections from Colin Mochrie's head) of the advertising industry comes from the fact that it's never made much sense.
Internet advertising is a great deal more quantifiable than TV, radio and print ads (which isn't to say that Internet ads are very quantifiable; it's just that before that everyone was really making up numbers). But just because you know the quantity doesn't mean you have a clue about the quality.
Advertisers used to be billed according to some vague idea of how many people saw their ad, whether those people cared about it or not. Now advertisers can opt to pay only when someone clicks on an ad. And that's opened up a whole new can of worms.
Take the Google ads on this site, for instance. I get paid when (or, more realistically, if) you click them. Google will be cross with me, though, if I tell you to click them. They would, in fact, prefer you not to click the ads if you have anything but the purest of motives.
Whenever anybody clicks on an ad when they are not actually interested in doing whatever it is that the advertiser wants them to do (usually, buy something), that's click fraud. Maybe "fraudulent" clickers are doing it to make money for a site that they like (or, in the purest form of click fraud, a site they own), or maybe they're doing it to hurt someone they don't like.
This issue becomes quite important when you consider how much money people spend for some pay-per-click ad campaigns.
Google's AdWords system, for instance, lets advertisers bid for particular keywords. Basically, when a given keyword appears in a Google search or on a page that runs Google ads, then whoever's bid the most for it gets their ad displayed. Lower bidders, if any, get their ads displayed lower in the list. You can bid any amount you like - I'm sure there are zillions of bottom-feeders who've bid a few cents for all kinds of popular keywords - but if there are a few higher bidders who haven't hit their budget limit, your ad will never be seen.
Google's Keyword Tool is free to use whether or not you've got any kind of Google account. It lets you pretend you're interested in some keywords and see the estimated cost per click (CPC) for them.
Mesothelioma is a favourite of ambulance-chasing lawyers; as I write this, Google's estimated CPC for that keyword alone is a hefty $US14.36. "Mesothelioma attorneys" was $US25.87.
"Debt consolidation" can be perfectly valid, but is often a big fat scam. "Debt consolidation chicago" was estimated at $US30.92 when I checked.
Oh, and name a scam, and it'll carry a healthy price per click. "White powder gold", for instance, is alleged to be a miraculous substance which is produced by no-kidding alchemy; it's bid up to around the eight US dollar per click mark, as I write this.
Herbalife? At least a few bucks a click - heck, the misspelled "herballife" is $US3.73, perhaps reflecting the value to multilevel marketers of customers who aren't too bright.
Ultrasonic pest repellers do not work. But the term "ultrasonic repeller" will still cost you around three bucks a click.
I was initially disappointed by the bids for terms relating to various bogus fuel saving gadgets ("water powered car" was only 52 cents). But then I found "gas pills", which are as stupid as they sound and cost a not-too-shabby $US1.42.
When you can cost someone several dollars just by clicking an ad, it becomes tempting to do so. Just do a Google search for whatever you least like, see if the Sponsored Links include an ad for someone who's trying to sell it to you, click the ad. Bing - money will now be moved from them to Google.
Better yet, find a page that has Google ads on it and is against whatever you least like, and click any ads on it that're from people trying to say the opposite.
The Google ads on Theodore Gray's Periodic Table Table site, for instance, are often weird quacky stuff. Look at a page for a toxic metal and you'll often find an ad from someone eager to find it in your body with a bogus test and/or remove it from your body with a bogus treatment, and at the moment his hydrogen page seems to have attracted a lot of bogus hydrogen power ads. Google reserve the right to just not accept clicks that they consider to be fishy in some way, but there's no way for them to tell whether someone clicking on a Creationist ad on a page about evolution is doing it out of genuine interest or not.
So, with just a click, you can cast your own vote against any advertiser. And if you only click one ad, and that ad wasn't presented in a way that contravenes any of the ad network's rules, then it's singularly unlikely that your click could be told, in any way, from that of a perfectly genuine shopper.
When payments per click are in the single-digit cents, such a vote doesn't matter much. When they're in the double-digit dollars, it does.
I can't wait to see how the next brilliant idea in advertising will go wrong.
(Incidentally, affiliate programs that only pay out when someone buys something avoid this problem. I could put flashing scrolling CLICK HERE!!!!!1! exhortations around my links to Photonlight.com or any one of Ron Toms' various and delectable sites, and all that would happen would be that they'd be somewhat taken aback. They don't pay me a penny if the clicker doesn't become a customer. My Aus PC Market sponsorship ads on Dan's Data, though, are pay-per-click. So don't go clickin' on them like crazy just because you want me to be rich; all that'll happen is that they'll ignore your IP address and/or reduce the amount they pay per click. Donations, of course, are always welcome!)