Now that you mention it, wouldn't click fraud be an excellent money laundering environment? All these bullshit content farms (taboola, outbrain, etc) that provide no value to the people actually using the web -- it's just a paycheck to publishers, where is the value coming from?

People are buying and selling click traffic (likes, follows, youtube views), suppose you just buy advertising and it gets placed on domains all over the web -- if I want to transfer money to you, you just need to spin up a domain, get taboola recommending some gut health articles, and I can buy ad placements and point my botnet at your domain, clicking on the ads I paid for so you get all the kickbacks -- something like that I'm not in the ad brokering business myself! Or the money laundering business for that matter :)