ANY "next big thing" sold on the internet has a short self life these days. We've seen it happen with all the flavors of porn. But if you hit while it's hot, you have the capital to hit the next one
A friend of mine who used to be in porn got out a few years ago. He started with cell phones, hit big, they started dying down. Went to credit cards. Hit big, died down. Next up, health insurance. Then mortgages. Right now he's doing payday loans. Once they die down, he'll do what he did with the others - keep them on the back burner so they still bring in sales, but focus on the "next big thing".
Being adaptable on the internet is imperative.