Parasitic Advertising
  
When a company cannibalizes itself with ads, we call it parasitic advertising. Yep, sucking the blood out of themselves. What's being cannibalized? User experience. That is, the otherwise-good-site is so crapped up with ads that users get pissed off, and the good will they felt toward using the site gets sucked away.
To be fair, parasitic advertising can also refer to the experience wherein one firm is stealing some of the market share from another firm by advertising a similar product.
Say you work for a firm that makes dog collars for dogs that are bad at taking walks with humans. Your firm comes up with a slightly different, but very similar collar, and advertises it. Sales for the old collar drop, and sales for the new collar rise. Good job...you just moved around customers, and didn’t earn new ones. Womp womp wommmmp. You just cannabilized yourself.
But you’re not done there. Cesar Millan is suing your company for your parasitic ads of his very-similar collar for dogs that are bad at taking walks with humans. This is the other side of parasitic advertising.