if you have had a website for a while, you likely know what SEO means and the importance of it. If you are new to the web, SEO stands for Search Engine Optimization. In other words, it is how to make your site more attractive to search engines so you end up on pages 1 to 3 rather than page 100 in a search for products like yours. Many things affect your attractiveness to search engines; popular search terms, frequently updating your site, etc.
Since Google basically has the market share of searches, they set most of the rules that website developers must know to make your site more attractive to Google. From time to time Google changes the rules and if you don’t change your site with it, or have your developer do it for you, you may slip from page 2 to page 20.
One example of this is the frequency with which you update your site. At one time the search robot algorithm wasn’t concerned with how often you updated your site. Why would you? You put your site up, people liked it, you had a decent conversion rate (searches to sales), and your product line hasn’t changed – price included. But Google decided that if you didn’t update your site at a certain frequency rate that your site was stale and fell in the hit rankings. This is why you have blog posts on a regular basis. Your site is updated regularly and the robot knows it. You move back up in the rankings.