This is very much in the spirit of what we were trying to do with trove.to [1] — give people an easy way to curate & annotate lists of websites, and layer a social graph and endorsement system on top of those lists.

The problem we encountered is that the vast majority of people are not hyper-organized list makers — the 1% rule of the internet [2]. To create a "human curated search engine" with any utility, you need a massive amount of manually-categorized data — data which most people are simply not interested in generating. This is why no social bookmarking site (e.g. delicious, pinboard, etc.) has ever taken off to hundreds of millions of users.

I still think there's something exciting to be built here, but it will likely need to take a more "automated" approach as you suggested.

[1] https://trove.to/

[2] https://en.wikipedia.org/wiki/1%25_rule_(Internet_culture)