It's a familiar interface to every developer, and means that solutions to problems are stored in an easy-to-read, searchable format so we're not left scratching our heads trying to remember what we did to resolve a particular error message that we came up against in the past.

Being able to collaborate on StackOverflow with use case-specific problems is very helpful.

It lets developers to solve questions to their team mates, and also to keep a FAQ-like documentation for common asked questions about processes and private repositories.