Ask HN: How do you find an *expert* in CS?

Say that you're trying to implement a complex new feature, or that you've found a critical bug in your system. The time arrives when you see yourself staring at the screen without answers. You've tried Stack Overflow, Google, Github, IRC, anything! What do you do? How do you find someone to help you work that thing out?

Disclaimer: I'm asking this because I'm working on a project that aims to help people finding experts to unlock their critical issues. And I need to first understand if I'm the only one seeing this as an something that needs to be improved.