Making a lot of money with the stock market isn't easy, but smart people shouldn't have much trouble earning with it.
Forex is generally thought of as a tough way of earning, but for smart people making money with it can actually be very simple.
Anyone can start a blog, but it takes brains to be able to earn a lot of money with one.
Writing high-quality articles quickly can earn you a lot of money, but it's something that requires a decent amount of intelligence.
You don't really need to be smart to write an ebook, but being clever can help you earn a lot more than the average author.