Search Engine Optimization or SEO is an online marketing strategy that utilizes both on-site optimization and off-site link building, to increase organic traffic to a website, for a particular set of keywords Pay Per Click or PPC is a search auction where you create ads and then bid on different phrases for those ads. Your ads appear above and below the non-paid organic search results. Higher bids have a better chance of the #1 position. The search engine is then paid every time a user clicks on your ad.