Internet marketing, also referred to as web marketing, online marketing, or eMarketing, is the marketing of products or services over the Internet.

The Internet has brought many unique benefits to marketing, one of which being lower costs for the distribution of information and media to a global audience. The interactive nature of Internet marketing, both in terms of providing instant response and eliciting responses, is a unique quality of the medium. Internet marketing is sometimes considered to have a broader scope because it refers to digital media such as the Internet, e-mail, and wireless media; however, Internet marketing also includes management of digital customer data and electronic customer relationship management (ECRM) systems.

Internet marketing ties together creative and technical aspects of the Internet, including design, development, advertising, and sales. Internet marketing does not simply entail building or promoting a website, nor does it mean placing a banner ad on another website. Effective Internet marketing requires a comprehensive strategy that synergizes a given company's business model and sales goals with its website function and appearance, focusing on its target market through proper choice of advertising type, media, and design.

Internet marketing also refers to the placement of media along different stages of the customer engagement cycle through search engine marketing (SEM), search engine optimization (SEO), banner ads on specific websites, e-mail marketing, and Web 2.0 strategies.

Business Models
Internet marketing is associated with several business models:

• e-commerce - goods are sold directly to consumers or businesses,
• publishing - the sale of advertising,
• lead-based websites - an organization generates value by acquiring sales leads from its website, and
• affiliate marketing - a business rewards one or more affiliates for each visitor or customer brought about by the affiliate's marketing efforts.

There are many other business models based on the specific needs of each person or business that launches an Internet marketing campaign.

Advantages
Internet marketing is relatively inexpensive when compared to the ratio of cost against the reach of the target audience. Companies can reach a wide audience for a small fraction of traditional advertising budgets. The nature of the medium allows consumers to research and purchase products and services at their own convenience. Therefore, businesses have the advantage of appealing to consumers in a medium that can bring results quickly. The strategy and overall effectiveness of marketing campaigns depend on business goals and cost-volume-profit (CVP) analysis.

Internet marketers also have the advantage of measuring statistics easily and inexpensively. Nearly all aspects of an Internet marketing campaign can be traced, measured, and tested. The advertisers can use a variety of methods: pay per impression, pay per click, pay per play, or pay per action. Therefore, marketers can determine which messages or offerings are more appealing to the audience. The results of campaigns can be measured and tracked immediately because online marketing initiatives usually require users to click on an advertisement, visit a website, and perform a targeted action. Such measurement cannot be achieved through billboard advertising, where an individual will at best be interested, then decide to obtain more information at a later time.

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. Usually, the earlier a site is presented in the search results, or the higher it "ranks," the more searchers will visit that site. SEO can also target different kinds of search, including image search, local search, and industry-specific vertical search engines.

As an Internet marketing strategy, SEO considers how search engines work and what people search for. Optimizing a website primarily involves editing its content and HTML coding to both increase its relevance to specific keywords and to remove barriers to the indexing activities of search engines. Sometimes a site's structure (the relationships between its content) must be altered too. Because of this it is, from a client's perspective, always better to incorporate Search Engine Optimization when a website is being developed than to try and retroactively apply it.

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. Because effective SEO may require changes to the HTML source code of a site, SEO tactics may be incorporated into web site development and design. The term "search engine friendly" may be used to describe web site designs, menus, content management systems and shopping carts that are easy to optimize.

Another class of techniques, known as black hat SEO or Spamdexing, use methods such as link farms and keyword stuffing that degrade both the relevance of search results and the user-experience of search engines. Search engines look for sites that employ these techniques in order to remove them from their indices.

Social media optimization (SMO) is a set of methods for generating publicity through social media, online communities and community websites. Methods of SMO include adding RSS feeds, adding a "Digg This" button, blogging and incorporating third party community functionalities like Flickr photo slides and galleries or YouTube videos. Social media optimization is related to search engine marketing, but differs in several ways, primarily the focus on driving traffic from sources other than search engines, though improved search ranking is also a benefit of successful SMO.

Social media optimization is in many ways connected as a technique to viral marketing where word of mouth is created not through friends or family but through the use of networking in social bookmarking, video and photo sharing websites. In a similar way the engagement with blogs achieves the same by sharing content through the use of RSS in the blogsphere and special blog search engines such as Technorati.

Social Media optimization is considered an integral part of an Online Reputation Management (ORM) or Search Engine Reputation Management (SERM) strategy for organizations or individuals who care about their online presence.

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, and paid inclusion. Other sources, including the New York Times, define SEM as the practice of buying paid search listings.