Local Search Optimization is what LSO stands for and Local Search Marketing is referred to as LSM. Both these factors are further derivations of SEM. In case of local small businesses these are considered. The local search optimized business can focus on the search terms relevant to the geo-location in order to generate high ranking. Though SEO is free, SEM along with being more expensive is also probably more targeted. SEM is generally considered by people after they have taken full advantage of SEO options. SEO lays out the foundation for SEM to get results that are better and affordable.