Can you mention the difference between SEO and SEM?

[shakthipriya]

The difference between SEO and SEM is simply that Search Engine Optimization is part of Search engine marketing or Search marketing as it is widely known. Both processes aim in increasing visibility in search engines.

SEO is about optimizing your website to get better rankings in the search results while SEM goes beyond SEO. It involves other methods that can get you more search engine visitors like PPC advertising.