On-Page or Off-Page Content.
Increase Business Goal Achievement Rates.
Refine Traffic Quality.
Some SEO is done outside of your website, but most SEO has to be done within your site to ensure a good customer experience. Done well, it can transform a website from generating little in sales or leads, and turn it into a sales star performer, but ultimately: getting 1000 high quality visits is better than 5000 low quality visits. High quality visits are more likely to turn into customers.