SEM

SEM - Search Engine Marketing.  The objectives of SEM are to (1) attract visitors to your website and (2) have them "convert."  A conversion is defined differently depending on your site's objectives.  For example, if you are selling products through your website then you may define a conversion as a purchase.  If you are a service-based company you may define conversion as the submission of a "contact us" form.  SEM is broader than SEO, and may incorporate SEO into the overall marketing plan.  SEM may include pay-per-click advertising.  It reviews web traffic analytics and measures goals and conversions.