I think the key here is that it's a feed managed by the user. There's not enough commercial potential in that. As a tech company, you want to be the one curating the feed, and you want the user to believe you're doing it in their best interest so they don't notice how you're making money by subtly feeding them ads.
RSS is simply too good for the contemporary internet.
Looks promising.
I'm setting it up now, was close to give up when it continuously refused to work after setting up an account. Turns out the passwords randomly generated by Firefox is a bit too hardcore for it, I changed to something with fewer special characters and now all is good. :)
Edit: It worked for setting up the interface and my profile, but I still cannot sign in from within it. Seems like a promising project though.
Edit edit: Moved it from a subdomain to a normal folder, now I can sign in, but it still acts a little broken, and doesn't federate. Oh well, I'll see if I'll tinker more later.