I do think the idea has a lot of merit. I've seen collaborative filtering work very well in movie recommendations, and I've observed in real life how often social groups overlap with multiple similar interests.

I think that scaling will be a challenge, both computationally and gathering enough data to be meaningful. The biggest wins, I suspect, are when you can infer people's preferences incidentally (say, from watching what podcasts they actually talk about on social media) rather than from their self-reported preferences, where conscious intentions often override true emotions.

But I'd love to see this work. I know there are things out there that I'd enjoy but don't manage to connect with.