If you’re starting or running a small business, particularly a high-tech small business, web-related, and you don’t know this pretty well, I suggest you click and read The Importance of Google PageRank: A Guide For Small Business Executives on HubSpot’s Inbound Internet Marketing Blog.
This strikes me as a quick and easy summary, going through the fundamentals very well.
Quick recap: Organic search is like free advertising. It’s worth the investment to try and get a high ranking by the major search engines. To rank high you should do two things: First, make sure your site has the right relevant content for the types of searches your potential clients are conducting. Second, try to get the highest PageRank possible. To do this, you need to get as many inbound links from as many high PageRank web pages as possible.