Is there a market for this idea?

As for ESL -- you do not necessarily need to know another language to teach English - a lot of people in Latin America (specifically Costa Rica) want to learn English and pick it up pretty quickly. That is why when American Expats go to Costa Rica they have a hard time fine-tuning their Spanish, since the locals want to learn English.

I think you have something! Seriously.

Easy. You are the face to an online brand. If you are credible, people will be buying YOU (your expertise/your legitimacy) instead of the, faceless generic albeit free, competition. Being in the United States gives you a clear advantage. You just need a Korean or Chinese partner. Since I am neither, I can't help. Still, I KNOW this can be huge because I have a former employee who is working (was working) for a small scale tutorial Skype-based service. I am betting the quality isn't anything to write home about. Now, if YOU had a branded tutorial service, it might make quite a nice chunk of change on a recurring basis.

In this particular forum, the consensus is that you should think of your market first. After all, it's a marketing forum, not a product development forum.

Coming as I do from the software development industry, my twenty years in engineering saw every single product done exactly the opposite way: first you build something, then you go find people who want it.

Frank Kern recently "retired" from internet marketing to focus on his offline consulting, and then came back like Prometheus bearing fire from Mount Olympus yelling "guys, guys, we've been doing this backwards all along."

But from where I sit, neither one is "better." Both are important. If your product doesn't have a market, then it doesn't matter how well-engineered it is. If your market doesn't need a product, then it doesn't matter how well-targeted it is.

But you have to start with one of them. And you have to lock down what it is and what you're doing with it.

If you decide to focus on the market, then pin down your business on getting that market's attention and becoming a recognised expert in that market. You can try any number of products once you do that.

If you decide to focus on the product, then make it the best damn product you can that does exactly what you want it to do. You can sell it to any number of markets once you do that.

One of these things will be easier for you. Some people will say to start with that. I say do the opposite - start with what's hard. Because whichever one you choose, you'll do a lot of work on getting it locked down before you can get to the other one, and you'll be tired. So do the hard one first, and then when you're tired you'll be looking at an easy job.

Others argue that if you do the easy job first you won't be tired and you'll have the momentum of what you just did to help you through the hard part. I get that. I see the logic. I just have a different philosophy. Not necessarily a better one.

You can see the economics background showing. "On the other hand..."

It sounds to me like you have a product planned out, and you aren't sure of the market. So instead of trying to lock down the market and tweak the product to match, I'd lock down the product and be done with it. Then you can try all the markets you want - your product is done. Go try to sell it over here. If they don't want it, go try and sell it over there. If you can't sell it anywhere, start looking at the reasons why and tweaking the product.

The content you generate can be repurposed as well; you can bind it all up in one large hardbound book, sell it as one monolithic ebook, put it on Kindle as short chapters, condense it into an SAT study guide, deliver it via email over an autoresponder, drip-feed it into a blog via paid subscription... content is absolutely king. I really like the Kindle idea; you should totally do that. Take a week's lesson plan and stick it on Kindle for $2.99; what's the worst that could happen? You don't make any money? Why, that's no worse than you're doing now.

Repurposing totally works. Robert Kiyosaki wrote exactly two books - Rich Dad, Poor Dad and The Cashflow Quadrant - which he has gone on to rehash and creatively edit into over twenty more books. Some people own over a dozen of them (guilty). And the autobiographical bits aren't even true. Hell, look at the Chicken Soup for the Soul books - they're pretty much the same damn book over and over, and they don't even pretend to be anything else.