Some attainable leads to include things like Wikipedia’s site on SEM being entirely skewed towards paid efforts; Yahoo’s push in their PPC Option; and the general alphabet soup of perplexing marketing and advertising acronyms. (For an in depth historical past on the time period SEM, see Danny’s recap from 2010.) http://sem13343.blogoscience.com/4496710/rumored-buzz-on-สอน-seo