SEO is search engine optimization and search engine marketing SEM is , they are different. Necessarily , this is indeed a lot of people mistake the place . SEM by the different methods and strategies to improve the composition of propaganda site , in other words , SEO is a part of SEM . Indeed , SEO SEM may be the most important methods used today . Currently , SEM is in the development stage , it will become in the future development of electronic commerce and even professional websites only way . SEO is part of belonging to the SEM , SEM includes SEO. SEO and SEM is most important is different ultimate goal , SEO is mainly to keyword ranking, site traffic , site structure , pages indexed in the search engines through SEO SEM data technology based on the expansion of the search engines brought to business value , planning effective network marketing program , including a series of site operations strategy analysis and implementation , marketing effectiveness testing. Although SEO and SEM services is almost the same purpose, but is always recommended to use both to achieve the best results. SEO shows your natural search relevance and SEM makes you always shoot at the front .