I think exploring revenue streams behind a website or online service is always interesting, particularly in the startup stages of a development. There’s the likes of contextual advertising, affiliate advertising, premium content, ebooks…..

With ebooks in mind, 37Signals seem to be onto a winner with their latest book. They’ve just launched their latest electronic download at a princely sum of US$19. How many did they sell on the first day? A grand total of 1750 – thats only the first day.

Now people…. $19 x 1750 = $33,250 – thats a whole lot of cash for a book you’re publishing and releasing yourself.

Kottke.org takes a short, interesting look at it… I guess good content with a strong audience really pays off on the web!