This resonates with one idea I've had. A email-only service: I subscribe to your email and get notifications when you find something interesting in the internet

This resonates with one idea I've had. A email-only service: I subscribe to your email and get notifications when you find something interesting in the internet and post a link to the service. Interactions with the service don't need a website. You literally send a email with a link to news@foobar,com, the service sees where the email came from, adds the link to your newsfeed and distributes it to your subscribers. Ideally, you wouldn't even need to setup an account, just send a link from any email and your account is that email. Subscribing to someone's email could be as simple as sending a "subscribe to joe@schmoe,com" to the service.