There is also much confusion between the notions of similarity and relevance. These are not the same thing. It has often been said by many companies doing topic clustering, document filtering, and other such applications that their algorithms function by grouping relevant documents together. What is actually meant is that the algorithms are grouping similar documents together. Two (or more) documents are never relevant to each other. They may be similar to each other, but they are only ever relevant to a user’s information need. If there is no user information need, there is no relevance.

The cluster hypothesis in information retrieval says that two documents that are similar to each other have a high likelihood of being relevant to the same information need. Documents by themselves, however, are never relevant to each other. Relevance is defined in terms of a user’s information need.

This guide is licensed under the GNU Free Documentation License. It uses material from the Wikipedia.

A significant number of firms, from small businesses to multinational corporations, incorporate online advertising into their marketing strategy. This is even true of firms which conduct their business through more traditional brick and mortar channels. In response to this demand, a number of firms specialize in facilitating online marketing. Therefore, online advertisements typically involve at least two separate firms: the advertiser or agency which purchases or sponsors the advertisement and the publisher or network which distributes the ad for display. Additional parties may also be included, such as an ad serving technology provider, a third party sales network, or other combinations.

In capitalizing on the increasing importance of the Internet as a marketing medium, the online advertising industry has developed specialized technical systems to manage the ways ads are distributed and viewership totaled. The Internet Advertising Bureau (IAB) has established guidelines for the counting methodology, size requirements, and other aspects of the business.

Because of the close relation between technical innovation and online advertising, many firms specialize in both. For example, most search engines couple their search service with an advertising program, exploiting the benefits of keyword-based search technology by including ads in search results. Many technology firms specialize in ad serving, the systems used to select the ads to show, optimize results, and generate reports.

Email advertising

Legitimate Email advertising is often known as opt-in email to distinguish it from spam.

Affiliate marketing

Affiliate marketing is a form of advertising where the advertiser allows a potentially large number of small publishers to pick specific creative elements or offers to market in exchange for payment should such marketing create sales or other revenue. This is usually accomplished though a self-service online system, such as those offered by third parties Performics, BeFree, CommissionJunction, or Linkshare. Affiliate marketing was an early innovation of online retailer Amazon, which has used its program to generate enormous volumes of low cost brand exposure.

Contextual advertising

Many advertising networks display text-only ads that correspond to the keywords of an Internet search or to the content of the page on which the ad is shown. These ads are believed to have a greater chance of attracting a user, because they tend to share a similar context as the user’s search query. For example, a search query for “flowers” might return an advertisement for a florist’s website.

Another newer technique is embedding keyword hyperlinks in a webpage which are sponsored by an advertiser. When a user follows the link, they are sent to a sponsor’s website.

Ads and malware

There is also class of advertising methods which may be considered unethical and perhaps even illegal. These include external applications which alter system settings (such as a browser’s home page), spawn pop-ups, and insert advertisements into non-affiliated webpages. Such applications are usually labeled as spyware or adware. They may mask their questionable activities by performing a simple service, such as displaying the weather or providing a search bar. Some programs are effectively trojans. These applications are commonly designed so as to be difficult to remove or uninstall. The ever-increasing audience of online users, many of which are not computer-savvy, frequently lack the knowledge and technical ability to protect themselves from these programs.

Links

• IAB

This guide is licensed under the GNU Free Documentation License. It uses material from the Wikipedia.

AdSense for feeds

In May 2005, Google unveiled AdSense for feeds, a version of AdSense than runs on RSS and Atom feeds that have more than 100 active subscribers. According to the Google Blog, “advertisers have their ads placed in the most appropriate feed articles; publishers are paid for their original content; readers see relevant advertising — and in the long run, more quality feeds to choose from”.

AdSense for feeds works by inserting images into a feed. When the image is displayed by the reader/browser, Google writes the ad content into the image that it returns. The ad content is chosen based on the content of the feed surrounding the image. When the user clicks the image, he or she is redirected to the advertiser’s site in the same way as regular AdSense ads.

AdSense for search

A companion to the regular AdSense program, AdSense for search lets website owners place Google search boxes on their pages. When a user searches the web or the site with the search box, Google shares any ad revenue it makes from those searches with the site owner.

Abuse of Google AdSense

Some webmasters create sites tailored to lure searchers from Google and other engines onto their AdSense to make money from clicks. These “zombie” sites often contain nothing but a large amount of interconnected, automated content (e.g. a directory with content from the Open Directory Project). Possibly the most popular form of such “AdSense farms” are splogs (“spam blogs”), which are centered around known high-paying keywords. Also many sites use the free Wikipedia content to attract visitors. These and related approaches are considered to be search engine spam and can be reported to Google.

This guide is licensed under the GNU Free Documentation License. It uses material from the Wikipedia.