Search Engine Marketing (SEM) tactic seeks to increase the web presence of business through online networks. Some people tend to think of SEM and SEO as the same thing but there are some subtle differences. The Search Engine Marketing Professional Organization (SEMPO) includes SEO in its industry definition by SEMPO industry experts. But, organizations like New York Times differentiate SEM as the “practice of buying paid search listings”. This is the most effective way of reaching valuable customers.