Ads on the web
The ad people don't seem to get it. If you make adverts intrusive and annoying, people will start ad-blocking. Once they start blocking, they won't stop. Running a fucktonne of 3rd party JS counts as intrusive and annoying. Advertisers are the ones who have killed the goose etc.
If someone could come up with a decent micropayments service for accessing things like news, that might be better. I pay for news sites I use all the time, but I'm not going to subscribe to sites that I look at 5 times a month.