Here's how you can make money through ebook writing:

1. Sell your own ebooks. 
2. Use your ebooks are traffic-generating tools. 
3. Write ebooks for other marketers. 
4. Use your ebooks in your list building campaigns. 
5. Sell ad spaces to marketers. 
6. Use your ebooks as viral marketing tools. 
7. Use your ebooks to brand yourself as an expert on your chosen niche.

via ezinearticles