In simple terms, Pay-Per-Click Advertising (PPC) is a fast way to appear at the top of search results where you only pay the search engines every time a user clicks on your advert.
PPC can have a very fast impact on your website and business. The ultimate goal of your website will usually be to build your organic (free) traffic to your website through various Optimization Methods, but that is usually an ongoing and long-term process. PPC can bring you almost immediate measurable results.