Presumably because, as they move out of beta, they want people to start paying to use their search engine. Thats the only way they can afford to be ad-free.

I'm 100% happy to pay for an ad-free search engine that doesn't sell my data. I don't really like having all my search terms being linked to me via an account, but I suppose that's already happening anyway. I guess I picked the right day to stop looking at clown porn.

I guess how would you implement monetization without an account in some form ?

You could just allow a given IP address ? But that's just as trackable and has tons of downsides with using from other locations.

They could do the SaaS model and give you an API key or unique URL allowing up to 10000 searches per month which you could share with friends/your company

That's probably a worse business model, but it would be really interesting to hear what other monetization ideas Kagi considered or is considering.

Works at an enterprise level (e.g. exchange rate providers) but would be a bad fit for a B2C product.

Managing customer expectations on api key usage (esp. if that key is publicly visible e.g. URL parameter vs. HTTP header) is not worth it unless you have higher-priced products.

Also api keys would mean you might have to prevent re-selling, etc. Furthermore, they could still analyze api key usage to get the same historical data on you as if you logged in.

Would still link searches to your API key.

That's missing the point. If the same API key is used by 1000 people at a company, you don't have the expected 1:1 mapping of search terms to individuals with an account.

An individual account which isn't permitted to be shared is different.

You could sell tokens that get used up after each search or expire after certain amount of time since first use. Browser extension could store tokens and provide them to website as needed in random order. Tokens could be resold so no tracking by payment processor

To buy a token you still need payment details. How would this be different to just buying a subscription?

If you buy from reseller they have no way to correlate payment details to search queries. With subscription, however, service provider have your payment details and knows everything about your queries so it can build a profile on you.

yeah but they've been in "beta" for four years now.