I'd like to see a SO clone that has a subscription model that's optional but then when you upvote something you're giving that person some SO cash which they can cashout or apply to their monthly subscription.

Subscriptions would be a 'name your price' model, site would take like 10% + 2.8(stripe fees).

Questions would drop off indexes, related questions, etc after 1 year - but remain visible for 3 years, moderators can flag evergreen content as 'eternal', if they deem it likely to be relevant in 5-10 years, or part of pop culture...maybe have some flags they can give it like reddit posts. Archived | Popularity-extended-life.

Perhaps make invisible posts still visible to contributors, saved bookmarks, etc if logged in, but definitely won't show up unauthenticated or in google.

I think combining SO w/ something like codementor as well and code reviews would make for a good business model imho, really there's a lot of stuff in the 'learning to code space' that could apply.. could even have different views for questions --for instance people could post a video instead of text for a response, then you could auto load text or video or 'unified' views.

Lately I find myself using reddit more than SO, so maybe a customized reddit that's geared just for tech would be better... with slack-like communities built in, but the ability to wikify/read the chat logs online for further help/context.

Something that's broken by subtopics like reddit or into 'channels', w/ chat, wiki, and maybe built in awesome-lists, dev-docs, dev-tools, etc would be pretty sick.