For details on how I've made money from blogging, see: How to Make Money From Your Blog
That article is a bit dated, but it will give you the general idea.
Today my income is a lot more diversified. Adsense is no longer the biggest contributor. Most of my income now comes from profit-splitting deals with publishers whose products I recommend.
This month Learning Strategies is re-running their 59% PhotoReading discount
for StevePavlina.com visitors. I plan to make a blog post about it tomorrow. I learned PhotoReading two years ago and still apply it today, so it was a no-brainer for me to recommend it. Visitors who buy it get a hefty discount, Learning Strategies gains new customers, and I earn a commission, so it's a nice win-win-win arrangement. It's also a good way for me to keep my articles and podcasts free for everyone.
I evaluate TONS of personal development products and only recommend a small percentage of them because I'm incredibly picky. Publishers send me new items every week, so I always have a huge stock of materials to go through.
Currently I'm reviewing a new Learning Strategies program with Jack Canfield on the Law of Attraction -- 22 CDs plus an extensive workbook. I'm about halfway through it.
I love that I now have a way to generate income from studying personal development materials, which has been a passion of mine for more than 15 years. Before I ran this site, I read hundreds of books and went through dozens of audio programs that I paid a lot of money to buy... never realizing that I could actually earn money from reviewing and recommending the best products I encounter... simply by working out a profit-splitting deal with the publisher.
It's pretty funny how such great income-generating ideas will stare us in the face for years before we even notice them.