SEO techniques : Techniques that search engines recommend as part of good design referred to as White Hat SEO Techniques that search engines do not approve and attempt to minimize the effect of referred to as Black Hat or spamdexing.
SEM is the marketing process with a goal of getting more visibility in search engines either by getting more free traffic (SEO) or paid traffic (Paid search advertising).
Through paid search advertising you essentially buy advertising space in the search engine results. So instead of trying to rank higher and get free traffic you pay to appear in front of the searches.
The most well-known advertising agency for PSA is Google Adwords. Through Google adwords ...