|Basis for comparison
|Search Engine Optimization
|Search Engine Marketing
|It is a method used for maximising the number of visitors of a website by ensuring the higher position of the site by optimising the search.
|It is an online marketing technique which involves promotion of the website by increasing visibility of the site in SERPs with the help of optimisation and advertising.
|SEO is a part of SEM.
|SEM is a broad term used for traffic generation and is a superset of SEO.
|Obscure and long-term