Edit: Follow up question, concerning only the browsing feature: Improved Question Browsing & UI
I think it makes sense to improve cross community interaction!
One half of this would be to implement a way to have a single question shared by multiple communities (which was discussed some time ago: Allow cross-posting of questions to more than one SO site).
For example on a security related question about macos the following sites all overlap (depending on the specific question) but on SO there are 30 to 1 as many users (or worse).
- SO (6,000,000 users)
- Apple.se (153,000)
- Security.se (106,000)
- Crypto.se (31,000)
- Unix.se (188,000)
Looking at those numbers, as a question asker to get the best results it seems to make sense to post your question on SO rather than on any of the others.
My guess is that this relation only grows in numbers over time.
The other half would be to implement a way to browse questions from multiple communities.
As a question answerer, who in my case is a programmer (SO) that mostly works on mac (Apple.se, Unix.se) and is interested in Security & Cryptography I have to browse all 5 sites for questions that I can answer.