Q.What is the difference between SEO and SEM?
A. SEO stands for Search Engine Optimization and, in basic terms, means optimizing your website so that it ranks higher in organized search results. With SEO, you’re earning web traffic through unpaid listings. SEM, which stands for Search Engine Marketing, is typically used to describe paid search activities, as traffic is gained through the process of purchasing ads on search engines.
Social Media Tip: SEO and SEM can be confusing, and it doesn’t help that the rules keep changing. A good place to start is this SEO Periodical Table put together by Search Engine Land.