Here’s a little-known fact: Schoolteachers are some the most hardcore early-adopters on the Web today. This hyper-connected community represents an enormous opportunity for ed-tech entrepreneurs, and is the key to success for any ed-tech startup.

With the advent of social media, teachers across the world are forming enormous online communities and finding thousands of like-minded colleagues on Twitter and Facebook. Search for Twitter hashtags like #edchat or #flipclass, and you’ll find thousands of passionate teachers chiming into real-time conversations with their peers (a.k.a. “Twitter chats”). Browse through LinkedIn and Meetup, and you’ll find groups on just about any educational topic you could imagine.

So why is this important to startups? Just a few years ago, ed-tech startups had a harder time growing virally than their consumer-tech counterparts, since teachers weren’t near as connected. The standard practice for ed-tech companies was to ramp up sales and marketing to schools early in the product lifecycle, often pre-launch.

When the market winner is determined not by which company builds the best product, but rather which builds the best sales team, you can bet that user experience will suffer. And boy did it suffer.

Today, the “Global Teachers’ Lounge” is changing the game by enabling great products to spread virally. The new generation of ed-tech startups can focus on what’s most important — building a great product — and then achieve bottom-up growth through the teacher community.

Ed-tech entrepreneurs are in a much better position in 2012 than even just a few years ago. Here are just a few simple steps for them to build and grow their product with minimal resources.

1. Go where the teachers are.

Twitter, Facebook, and LinkedIn are your friends. See where the conversations are happening and join the dialogue. Don’t be afraid to go offline: Conferences and un-conferences like edcamp, ISTE, and #140edu are great opportunities to interact with and learn from innovative teachers.

2. Show, don’t sell.

Engage in a genuine way. Get offline and chat with teachers on the phone, even in person. Most teachers are happy to give you feedback, especially if you’re trying to solve their problems.

3. Iterate, iterate, iterate.

Regardless of the product, you should be following Lean Startup principles like the feedback loop: show your MVP to teachers, listen/measure, iterate based on feedback. Then repeat. You’ll know you’ve achieved product/market fit when you start blowing up on Twitter.

All of this boils down to one thing: Focus on building a great product. When you do, you’ll find a community of forward-thinking, early-adopting teachers just waiting to spread your gospel.