We have discusses SEO on here a number of times by now. If you are actively trying to earn your living online, or even a couple extra bucks, then you have come across the term. It stands for Search Engine Optimization, and that is exactly what it is. It is the act of optimizing your website so it will rank higher in the search engines.
Since search engines are responsible for directing a massive amount of traffic around the web it is a good practice to learn. Even the very basics, will be enough tot help your site out a bit.
This infographic, courtesy of Marketing Pilgrim is a great visual look at some SEO basics: