A lot of successful bloggers will write eBooks. Some of them give the eBooks away for free, maybe in exchange for an email address, social share or link to their website. Another way is to sell your eBook directly within your blog.

A perfect example of this in action is on the travel blog of Matthew Kepnes or 'Nomadic Matt'. Matt is an influential travel blogger and sells his eBook directly on his site here.

Advantages: There's big money to be made in selling an eBook on your blog. Not only this, but it can establish you as an 'expert' within your niche. If you're planning on putting in the work to do an eBook, you can also look at getting sponsors for the book to further monetize it, which can add to the profit potential.

Disadvantages: The main stumbling block here is the work involved in putting together an eBook. Even after you've slaved over getting your book together, you'll need to do a lot of promotional work to advertise it, which will usually mean spending some money.

If you don't have cash to promote the eBook with, then you might risk not making a return on your time.