What is the difference between SEO and SEM services?

There’s a vast difference between SEO and SEM services although they might seem to be used interchangeably. Both are widely different from each other in their respective meanings and techniques. SEO includes all those tricks and techniques that we need to adopt so as to increase the website traffic and also to make it search engine friendly. However, SEM stands for search engine marketing, which itself includes SEO services and other marketing tools like requesting back links, URL submission at search engines etc. to get our page ranked high in the search engines.
When you are searching for SEO and SEM services make sure to check the details of the company providing the following services because many companies only do URL submission to popular search engines in the name of SEM which you can do yourself also. There’s a list of search engines to which webmasters need to submit your site. Keyword optimization is also an important part of SEM. Do not forget to include the META tags and ALT tags.
So, we can conclude that SEM is more important than SEO because SEM includes both optimization as well as marketing strategies. Therefore, you need to be careful while deciding that whether you want only optimization services for your website or both optimization as well as marketing services.