What websites that aggregate content do you enjoy and what are some good implementations you've seen?

I am interested in making my own. As well as a open source software that streamlines the process of setting up a particular themed aggregate. Where the maintainer would just have to configure new sources and moderate comments essentiually. But this is just in the brainstorming stage ATM.

Also will be attempting automated classification of the data to organize it a bit better, while keeping hands off. Looking at stuff like openai.com for that.