Internet advertising is generally bought either CPC (i.e. per the advertiser pays the site for the number of clicks back to its own site) or CPM (i.e. the advertiser pays the site for the number of people that see the ad.)
- If the advertiser is paying the site that you're visiting (the publisher) CPM, it doesn't. The publisher gets paid because you showed up on the site and hopefully glanced at the ad. The world moves on, and everyone is happy. If you clicked on the ad thinking you were doing some good, you just wasted some bandwidth.
- If the advertiser is paying the site CPC, things get interesting. The publisher only gets paid by the advetiser if you click on the link. If you genuinely think the link might be interesting to you and you click on it, this is a good thing. The advertiser knows through experience that some percentage of people that click through to the advertiser's site will end up buying a product/service etc. The advertiser has used this and other data, to calculate a minimum price that he/she is willing to pay per-click.
Now, by clicking willy-nilly on ads on your favorite sites' pages, in the short-run and assuming that you're the only one in the world who does this once in a while, you are adding a little more money into the site's pocket. In the longer-run however, the advertiser has the data to see that they are getting fewer useful clickthroughs from that site.
They'll resort to measures such as reducing how much they are willing to pay for a click-through from the site, or even worse decide they don't want to waste their dollars on that site anymore. Oh and its gets worse. Ad Networks such as Google's Adsense may decide to penalize the publisher site that's leading to these inefficient clicks, most likely algorithmically.
- Nothing in life is free.
- Be yourself (i.e. don't alter your internet surfing behavior)