In this day and age, just having a responsive, informative website is no longer enough. Because of the massive amount of websites sprouting online every day, your own site is bound to get lost in the ever-changing sea of the search engine databases, making it very hard to find even for the most persistent and thorough of users.
The term SEO, which stands for search engine optimization, defines a range of practices aimed at helping your site climb through the rankings on search engine results, so that it is visible to more potential customers in your specific target audience. In order for this to happen, sites themselves have to be built in a way that allows search engines to efficiently crawl, index, and rank them, but they also need to be ranked for the right keywords if you want a high conversion rate for number of website views. Having your website rank #1 on Google for AC installments when you sell window replacements is not going to help you win over new customers!