I just started a website and want to put some ads on it to make it pay for itself. Given that nobody ever clicks on those, I thought that CPC (cost-per-click) is not an option and decided to go with CPM/CPV ads. Here's my question. What exactly stops me from putting hundred of those on each page of my web site and wrapping them into something like
<div style="visibility:hidden">ad banner</div>
The impressions/views would still be counted, right? Or am I not understanding something.
Putting aside the legitimacy and legality of what you suggest, ad serving is more intelligent these days than it was even just a few years ago. These days most ad networks use crawlers to identify the content on your site and better target ads to the end users based on the subject matter of your site. In doing this most of these crawlers also check to see placement of ads, competing ads, visibility of ads, etc. With this sort of check they can also see if javascript or CSS is being used to either make the block invisible to the end user or positioning it under other content or off the page. When this sort of coding is detected the ad networks have all sorts of methods at their disposal to deal with it, with most if not all simply deactivating ad serving on your site, and depending on the nature of the ad serving agreement and the country you are in and the site is targeted to they may even take legal action to recoup any money they have already paid to you under fraud laws. Basically there is no way to do this without being caught and the penalties if when caught can be very high.
