[anal_reactor]

This solution has been tried again and again and each time it failed:

1. Most websites that aren't dead had huge influx of new users at some point of their history. Recommendation system cannot handle that - it becomes a bottleneck, and people move to a competitor that doesn't have this problem.

2. Suppose you have a community and you say that each new user needs to be at least 99% compatible with what the community already stands for. Congratulations, your community will decay exponentially with each new user bringing the quality down just a tiny bit until it's gone.

The solutions that actually work tend to be UI-oriented. For example, 4chan has an outdated interface not because admins don't know to do modern UI, but rather because outdated UI filters off normies.

The biggest challenge is the balance between new users, who tend to bring the quality down, and old users, who are boring and have nothing to say beyond what has already been said.