I hadn't heard about YaCy even though I'm in their game. I too run a search engine that doesn't use a link graph for scoring relevance. My bet is on semantic relevance over PageRank, because I think our understanding of language models have become so sophisticated we can start relying on them solely.
Also, it's harder I think to game a language model when compared to a page rank model.
What do you think is lacking from non-link graph search engines?
EDIT: maybe I misunderstood b/c it says here YaCy _has_ a link graph: https://yacy.net/en/API.html
That link graph being referenced is the local nodes one, not a global one. So it only yields links that have been discovered by the node you are sending the request to.
You could send a request to each node individually and aggregate the results, however, you have no way to verify the nodes are being honest without actually crawling those pages yourself.
If I may ask, what is the project that you are working on?
I'm working on a project similar to the YaCy one. The main difference is that I do not want or even require that each node trust each other. I let the user decide who they trust.
Wait! YaCy is a little bit hard to understand. I don't mean that in any way other than in an extremely encouraging way.
What do you mean exactly? A YaCy node will interrogate the "swarm" of data and that interrogation might yield more links compared to if you interrogate another node?
What's that all about?
Esp, the disable personalized results.
In their privacy section they do admit to storing identifiable information for at least 7 days (possibly more) to fight spam and improve search results. They also send user identifiable information to bing, as well, who then store it for at least 4 days. Apart from that, they use third party tools in their non-search parts which might be subject to different privacy rules than their main website.
From their app, they send information to Facebook. They use the Amazon, Google, and Microsoft as advertisment providers, if I'm not mistaken.
I encourage you to read the fine print here: https://info.ecosia.org/privacy
Besides that everything I would expect from a search engine probably applies (Microsoft might get to know what I search for etc.).
But taking a little piece of cake away from Google isn't bad either.