How do you determine the profitability of a keyword?

I think I've found a good keyword to target, but I'm not sure yet. I won't reveal what it is, but I'll use a very similar one as an example... Let's say the keyword "how to create an ebook" receives over 10k exact searches a month - how profitable do you think this could be? My keyword is very similar, it's just not about ebooks (it's about another online hobby which has become quite popular in recent years - I'm thinking of promoting a Clickbank product that teaches how to do this particular hobby).

Thanks for any advice.

It depends on the competition as well for those keywords. How much time you can put into ranking them and getting to page 1. Utilizing all methods of getting links back to your site and getting traffic. You also have to monetize your site the correct way with good offers etc.

The profitability or otherwise depends on how you put your keywords to use as far as SEO, backlinking, etc., are concerned, and whether or not you can get ranked on page 1 of Google. Market Samurai offers a great too for checking competition on page 1 of Google.