Ironically I now work for an email marketing platform company, but it’s great work and we just provide the tools to annoy people. It’s our customers that actually do it (I know, I know).

My $.02 CPM is that yes, Reddit can improve their rates by improving relevancy. But they don't capture anywhere near the volume or quality of signals to inform relevancy models as compared to others in the space.

From their privacy policy it looks like they may engage with vendors who enrich data that can be tied back to a hashed identifier. This seems in sync with the increased pushes to create accounts with emails (one of the main identifiers the industry relies on) as well as use the app (to get a MAID, though those are increasingly worthless for identity resolution vendors from a match rate standpoint).

Reddit is in a tough spot because a huge chunk of their users want to use them anonymously, or with minimum PI provided. This leaves Reddit in a position of needing to either push harder to get it (like if they added profile fields to collect more PI), or infer it from modeling based on the subs you visit, content you read or post, interactions with other users, etc. Which puts them in the crosshairs of privacy bodies depending on how far they go.

This is all my own personal opinions and conjecture.

If you talk about buying a car on some random app, chances are that you'll then see ads on Facebook about used cars. Facebook gets to know what you do elsewhere, and offers advertisers extremely precise (and hence more valuable) targeting. That's what Reddit can't do.

Even back then, 100% of traffic Reddit ads was coming through Mobile, which explains why they really want (need) users on their mobile app. Desktop users just don't click ads, and mobile users using other clients don't see Reddit ads.

The tools available to me back then to run Reddit ads were a joke compared to other platforms, but with user acquisition was costing me around a dollar per user, I didn't really care!