The world and the internet does this anyway, with forums, meetups and anywhere else that people talk. Sites like HN, Product Hunt, and some subreddits do a grea

The world and the internet does this anyway, with forums, meetups and anywhere else that people talk. Sites like HN, Product Hunt, and some subreddits do a great job in the tech world, for example. There are other specialist blogs and subreddits for other interests - think Board Game Geek. The hard part is building a system that can't be gamed.