What is SEO and SEM?

What is SEO ?

SEARCH ADVERTISING
In Internet Marketing, Search Advertising is placing adverts on Web pages that show results from search engine queries. Through the same system, adds can also be placed on Web pages. (An automatic search related to the original query)

These adds are targeted to match key search terms (called keywords)
entered on search engines. This ability to target the search has contributed to the effectiveness of this medium to advertisers. Invariably people will use a search engine to identify and compare options immediately before making a decision on buying an item.

Thus presenting consumers with advertisements tailored to their immediate buying interests encourages consumers to click on search advertisements instead of unpaid search results, which are often less relevant. Unpaid search results are referred to as organic results.
PAY-PER-CLICK

Pay-Per-Click is a system where an advertiser pays an amount for each click someone makes on a link leading to their website.

This is also known as Cost-per-Click. The costs are dependent on keyword prices from the search engine, usually settled by an auction system.
KEYWORDS

A "keyword" is whatever you type in when you search on Google. Although you may type in more than one word when searching many people still call it a keyword as opposed to a "keyword phrase".

Search engines conduct auctions to sell adds according to bids received for keywords and relative relevance of user keywords to adds in the inventory.

The keyword "Cheap Cars" is more expensive than one that is in less demand, such as "yellow gravy."

Search engines build indexes of Web pages using a web Crawler (for example the Googlebot, or the MSNbot). When the publisher of a Web page allows adds to be served up on thier page, the search engine uses their index's to associate the content of that page with various keywords.

Advertising based on keywords in the content is called Contextual advertising.

Advertisers can choose whether to buy ads on search result pages (search advertising), published content pages (contextual advertising), or both. Bids on the same keywords are usually more expensive in search advertising than in contextual advertising.

What Is SEM?

Search Engine Marketing (SEM) is different to Search Engine Optimisation in that it provides the website owner with more control over who they connect with and the results generated. SEM allows the website owner to define things such as geography, customer demographic and search terms used to find advertisements placed strategically on the internet that drive qualified leads to your website.

Source from : seo-myths.com, webforcefive.com.au