[disgruntledphd2]

They need a pixel/SDK to make that work. That should have been step 1 in relevancy. Seems like they could also gave used their sharing buttons but whoever is running their ads strategy may not be focused on the right things (i.e. Dr advertisers from adult and gaming to start with).

[HDThoreaun]

Reddit definitely has a pixel. They don't have a 3rd party ad product though like FB and google so why would sites add it?

[disgruntledphd2]

For conversion tracking is generally why people add these.