This is one of my biggest loves of Kagi. I have all pintrest domain's blocked and it's great. And it's really easy to add a block too so when I get a result for a website that is useless or I don't like on to the blocklist it goes!

Yes. Quite useful. Also groups listacle spam ("top 10 X" type articles).

If they could group ecommerce sites in the same way they group listicles, that would be damn handy. (Just identifying sites with payment forms would go along way). It's not that I don't want ecommerce sites, it's just that sometimes I'm in research mode and sometimes I'm in shopping mode.

Being able to set up custom search weights would be cool. Like up-weighting results from sites you like and down-rating sites you don't.

It can do exactly this, as well as outright blacklisting. Very good stuff

Yes it’s a pretty handy feature

there are browser plugins that do this as well :) . uBlackList for one