Search engine marketing, or SEM, is a form of Internet marketing that seeks to promote websites by increasing their visibility in search engine result pages (SERPs). According to the Search Engine Marketing Professional Organization, SEM methods include: search engine optimization (or SEO), paid placement, contextual advertising, and paid inclusion.

A combination of Search Engine Marketing to run an internet marketing campaign may include:

* Search engine optimisation (SEO)
* Search engine and directory submission management
* Paid inclusion or Paid Placement
* Link popularity
* Articles submission
* ROI
* Performance Monitoring and Reporting (eg. Google Analytics Tool)

So in a nutshell, Search Engine Optimisation is basically a component of Search Engine Marketing.

Search engine optimization (SEO) is the process of improving the volume and quality of traffic to a web site from search engines via "natural" ("organic" or "algorithmic") search results.

The acronym "SEO" can also refer to "search engine optimizers," a term adopted by an industry of consultants who carry out optimization projects on behalf of clients, and by employees who perform SEO services in-house. Search engine optimizers may offer SEO as a stand-alone service or as a part of a broader marketing campaign.

SEO techniques can be classified into two broad categories: techniques that search engines recommend as part of good design, and those techniques of which search engines do not approve. The search engines attempt to minimize the effect of the latter, among them spamdexing. Industry commentators have classified these methods, and the practitioners who employ them, as either white hat SEO, or black hat SEO. White hats tend to produce results that last a long time, whereas black hats anticipate that their sites may eventually be banned either temporarily or permanently once the search engines discover what they are doing.