A great way to build on the reputation that your blog has is to offer training courses relevant to your niche.

This is done regularly within the online marketing industry and a great example, although not technically just a blog, would be with Jon Cooper's link building training course.

Advantages: There's loads of up-sell opportunities from offering training courses and it can easily be scaled if it is mainly self-teaching materials. Not only this, but you can start gathering email addresses from your trainees and start re-marketing to them.

Disadvantages: Putting together a full training course isn't a quick task. This monetization method takes a lot of resources, especially if you're going to be keeping it up to date and adding more information in the future.

Although there is high potential for revenue, it's not always an option for blog owners that don't have a lot of time/resources.