Ask HN: Is there an app for reading newsletters?

Is there some website that I could use to subscribe to newsletters? Something that would give me an email address that I could use to subscribe to newsletter, and that would then automatically organize them according to topics. Maybe even some kind of built-in bookmarking tool would be great and subscription management (unsubscribe, find similar content). Something like RSS clients but for newsletters.

I would like something that allows subscribing to newsletters from different platforms.

Is there a web/service/app like that?