Quote Originally Posted by sadianisar View Post
SEO: Search Engine Optimization.
It's a technique which is used to optimize a website according to search engine's rules and regulations.
Free of cost
Long term results
Slow process

SEM: Search Engine Marketing
It is a technique which is used to advertise your website on the top of the SERP by paying search engine for it.
Short term results (once you stop paying, you will lose your marketing)
instant results
Fast process
Expensive
Nice Explanation