Gosh, Stack Overflow thinks our little open-source project is a threat to them. I'm flattered! Also saddened.
For several years, Stack Exchange has allowed some of its sites to control some (local) ads. Communities can nominate ads that they think will be of interest to their own members, and if enough community members agree, those ads run. Mi Yodeya has ads to promote Sefaria, its own publications, and some other resources. Science sites have ads for professional and research organizations and publications. Several sites have ads that promote other related SE sites. Stack Overflow has ads for open-source projects looking for contributors.
The general philosophy is (or was) that the people building a site are the right ones to decide what to promote on that site -- they know their audience better than the company does. (Which, if you've seen some of the other ads the company runs across the network, is self-evident.1)
This week the company announced a change in qualifications for these community ads:
Community Promotion Ads (all non-SO sites)
The goal of this initiative is for future visitors to find out about the stuff your community deems important. This also serves as a way to promote information and resources that are relevant to your own community's interests, both for those already in the community and those yet to join.
Open Source Ads (SO only)
The goal of this initiative is to promote advertisements soliciting the participation and contribution of programmers writing actual source code. This is not intended as a general purpose ad for consumer products which just happen to be open source. It's for finding programmers who will help contribute code or other programmery things (documentation, code review, bug fixes, etc.).
Finally, ads can not be promoting products or soliciting programmer time or resources for knowledge sharing projects that are competitive to Stack Overflow, broadly construed.
Aw, the big 800-pound gorilla is afraid of a couple of small open-source projects! I'm honored that they think we're strong enough to compete with them, puzzling as that idea seems.
This is quite obviously targeted at Codidact and TopAnswers, down to using our "knowledge-sharing" language. (I bet they aren't really objecting to ads for Wikipedia!) We don't compete with Stack Overflow, of course. Stack Overflow does one thing: they try to make money with a library of answered questions about programming for search engines to hit. Anything else is secondary. This is in the nature of for-profit companies that have taken way more venture capital than they can realistically make good on.
Codidact and TopAnswers, on the other hand, are community-organized projects that place people first and aim to give communities more tools to build what works for them. Quality questions and answers are central, but communities can have other kinds of content too -- first-class content right there on their sites, not something they have to build elsewhere.2 We've got recipes on our cooking community, challenges on a few others, and a whole community built around competitive programming (code golf).
Codidact and TopAnswers are young projects with small communities and incomplete code. We're building as we go, building communities one person at a time, responding (often quite quickly) to requests for customizations or other changes. Codidact has two primary programmers and half a dozen other people who sometimes submit pull requests. (I think TopAnswers is similar.) We'd like to attract more people, sure, but our current team is doing a great job, one piece at a time, and we value that. We've got enough money to cover our server bills for a while at our current rates and should be able to take donations soon so we can expand. (We're already benefiting from some corporate freebies for non-profits.) We live within our means, financially and technically, and we exist at all to support communities of people building great things together. That's pretty different from SO -- our goals are different, our scale is different, our life-stages are very different. But they're still afraid of letting their users point to us.
Last year there were ads for Codidact communities on a few SE sites. They got there because they are "the stuff your community deems important" -- those communities voted for them. We on our project made a point of not going and mass-voting on those (even when employees were organizing their own voting rings against these ads). There was no fraud, no interference from outside, but interest from within those communities.
I wonder if that's why they're scared of us -- they've finally figured out that they need that pool of free labor, and they don't like that those communities have outside interests. That would be sad; society is enhanced by a mindset of "both/and" and diminished by one of "either/or".
1 Like ads for vitamin supplements, women's lingerie, men's hair loss, and the like. (Yes, I've seen those on professional-targeted SE sites.) The communities have no control over those.
2 A long time ago, for example, SE allowed its communities to have blogs on their sites. They eventually shut them down, and communities that wanted blogs were told to go set up on Medium or elsewhere. This is how I first learned about Medium; one of my communities, one that was doing well and drawing a lot of attention on the network, wanted a blog.