It`s very simple.

SEM means search engine marketing and search engine marketing includes the remaining categories i.

e.

SEO and PPC Search engine optimisation and pay-per-click.

Both of these terms are used for search engine marketing.

SEO gives you good results for long term basis but PPC gives you instant result.

You can use either both tactics for one website or any one for one website.

According to your desired ROI you can choose any one or both tactics for your business.

Alena rightly said that SEO and PPC are the branches of SEM.

SEM (Search Engine Marketing) also envelopes much logical ideas too for achieving considerable results for your online business.

The crucial point is on you how do you want to get the result of your business? If you want faster results, use PPC, and if you want to have a solid result with long time visibility in the Internet then use SEO.

SEO and PPC are the branches of Search engine marketing.

SEM – means everything which is connected with Web Marketing in search engines.

SEO improves the quality and the quantity of the traffic coming to optimised website from organic search.

PPC is a model of charging for advertising on search engines and websites.

SEO activities are mostly free but PPC activities are not free.

The result of PPC is faster than SEO.