Search Engine Optimization is the process of increasing your visibility naturally or organically (unpaid) for the keywords you want your webpages to rank for on search engines.
There are different ways to do SEO. Some tactics are considered black hat SEO (“the shady way of doing SEO”) and the standard way is called white hat SEO. SEO is not considered spam. Matt Cutts, the head of the web spam team at Google said, “No. We don’t consider SEO to be spam.” Watch the video below for more information:

SEO is not a quick process. If you are looking to rank for a highly competitive keyword such as “shoes”, you must be aware that you are going up against multi-million/billion dollar companies in the shoes industry who are already investing hundreds of thousands of dollars every month to rank on the first page. Although SEO may seem intimidating to small businesses, it is not incredibly difficult to rank up for long tail keywords which are less competitive such as “shoes in Boston” or “cheap red tennis shoes”. Rather than spending a great amount of money to try to rank up your website for a highly competitive keyword that might bring in 100,000 visitors per month, you can spend it smarter on PPC campaigns, paid search, or long tail keywords that will bring in the same or more amount of visitors for a lot less (250 long tail keywords x 400 visitors = 100,000 visitors per month).