It's been quite a while since I started working in tech. I've been in tiny startups, medium companies, and a few big companies; I've done both in-house development and consulting services, the later sometimes outsourced to clients for long periods; I've both seen from within workforces grow and adapt to change, and landed into already well-oiled machinery (theoretically at least).
You learn to recognize some people patterns, some archetypes, that typically either are already present or appear sooner or later. The superstars known in the community, the quick learners, the slower but methodical thinkers, the still-junior-but-will-be-awesome profiles... Some of these people will step forward and also help with the technical outreach, often by becoming speakers and/or participating in local user groups. But there will always be a subset, maybe just shy, maybe just not interested in public spotlight, that in any case won't shine so publicly (and sometimes even internally if the company is big enough), and yet get work done and sometimes achieve great things not expecting any ego boosting public recognition.
They don't speak at conferences, they might not have a blog, Twitter or any "social presence", or if they do they use it rarely... They just work, just focus on doing things the best they can. They usually excel and get great evaluations, and any time you ask about them to a colleague, the answer will always be positive. And if you speak with or, even better, directly work alongside them, you will always learn something new.
Those are the heroes who save the tech world, one company at a time. Those are the people I'm trying to emulate as of late.