I know how affiliate marketing works (though not an expert) but I can't comprehend in certain cases, where is the benefit of the ads (as in, who benefit from it?) when they relate to an open source project, that doesn't necessarily accept donation?
For example:
This ad was posted on one of the posts on Unix.SE. It links back to the GNU website. I'm aware the GNU project accepts donation, but I never thought they would use ads to get traffic...
And while they do accept donation, it's unsure whether they actually use the ads for that purpose. This is just one particular example where I'm unsure of the purpose of an ad (don't have other example at hand since I usually use an ad blocker).
Just curious and that doesn't mean I'm criticizing the ad itself or any of the concerned sites.
Just found out about the Free Vote-Based Advertising for Open Source Projects post by SO, but that still doesn't explain what's the benefit here?