It's a bit of a sliding scale. Are affiliate links like those used on hipmunk or Skyscanner ads? Amazon affiliate links? Cross links to other blogs that wordpre

It's a bit of a sliding scale. Are affiliate links like those used on hipmunk or Skyscanner ads? Amazon affiliate links? Cross links to other blogs that wordpress plugins add automatically? Job adverts on Stackoverflow? Links to the blogs of people who answer questions on stackoverflow? Blogrolls? I sometimes only realise a link is an affiliate when my hosts file blocks a 3rd party advertiser. It's impossible to know in general who has paid money for what links to third party sites and what agreements are in place behind the scenes. Half the time people probably don't even know they're clicking on ads.