Do you have any evidence (anecdotal or empirical) that people actually hire based on StackOverflow rankings? I'm sure it's happened in a few cases, but it seems backwards to me. If somebody came into an interview talking about their high SO rank or Reddit karma, I'd wonder if they would actually be focused on their work.
To me, hobbies and online activity aren't really credentials unless you've really built a strong personal brand that directly relates to your job.
To me, hobbies and online activity aren't really credentials unless you've really built a strong personal brand that directly relates to your job.