Internet marketing on search engines, more popularly known as search engine marketing or SEM, refers to those marketing methods aimed at making a Web site more visible on search engines. There are three basic methods of SEM: search engine optimization, pay per click advertising and paid inclusion.

1. 1. Search engine optimization
   Also known as SEO, this refers to those methods aimed at improving a Web site's structure, content, and backlink count. It gives a Web site's keywords more relevance when a search is made for these keywords and strengthens the Web site's ranking in search engine results. SEO is a very popular and effective Internet marketing technique.
2. Pay per click advertising
   This method involves a bidding on keywords by advertisers. If you place a bid, a search engine will insert your ads at the top of search engine results every time someone does a search for the keywords you bid on. In other words, the search engine will present your ads as "suggested sites" to those doing the keyword search.
   
   The ads are placed atop the natural search engine listings, and they are arranged according to the advertisers' bids, with those with the highest bids being placed at the uppermost portion of search engine results. It's called "pay per click" because the advertisers pay the search engine every time someone clicks the advertisers' ad.
3. Paid inclusion
   This method is similar to pay per click advertising except that, instead of placing an advertiser's ad on top of the natural search engine listings, the search engine includes the advertiser's Web site among the search results. This makes it appear like the advertiser's Web site is among the natural listings.
   
   The credibility of paid inclusion as an Internet marketing technique has received widespread criticism. In response, search engines such as Google ceased to offer this Internet marketing service in 2006.

By far, search engine optimization is the most widely-practiced among the Internet marketing techniques above. By re-designing a Web site to make its pages easier for search engines to find, SEO not only makes the site search engine-friendly, it also improves the site's overall aesthetics and its Internet marketing appeal. With the help of SEO, a site has a strong chance of landing within a search engine's top 10 results.

Internet marketing is also concerned with a site's choice of words and their placement, and SEO bolsters the site’s standing in this regard through the use of both visible and hidden meta tags. For the uninitiated, meta tags are HTML tags that contain information about the Web pages, including the name of the author, its subject matter, when it was created and last updated, etc.

Overall, there are two basic Internet marketing techniques for optimizing a Web site: (1) improving design and content to improve search engine results, and (2) spamdexing, which is stuffing the Web site with the key words. Try to avoid the latter.