SEO helps improve your website’s visibility in unpaid search engine rankings (also called organic results). If your website is placed higher in search engine results, you are more likely to receive increased traffic to your website. Knowledge of SEO will increase your traffic, thus bringing in readers and the potential to earn money through those readers.
PS: my answer to this question is always… “the better question is… how can my blog help me build a profitable business?” Most of the profits from blogging are not made on your blog, but that’s okay. I don’t believe blogging about making money per se, but about branding yourself and positioning yourself within your niche market as an authority and leader. Once that is established, there are so many ways to move people into your money making enterprises. Email marketing, as you pointed out, is one of the best ways to do this. Sending people to your membership sites, services, info products and coaching programs are all great things to route people into as well.
Don’t get me wrong I have made many mistakes along the way but once I knew what I was doing it became a lot easier and more enjoyable. Many of my friends have emailed me or called me to find out more about “What Jamie Does”, but it can be a little hard to sink in at first as to how you can actually make a real income from running a successful blog(s). Therefore I have decided to create this guide for my friends, family, email subscribers and anyone else who wants to start doing “What Jamie Does”.