A portal (or web portal) is a website that serves as a point of access to a digital environment by offering aggregated information and links to other websites from diverse sources in a unified way.^{1) 2)}

A digital environment can be the internet in general or a specific section of it (for example concerning a specific subject matter or language), a company intranet or others.

• Horizontal Portals: Also referred to as Internet Portals, they offer aggregated information on a broad variety of subjects and, through a Search Engine or extensive links database, web link information on potentially endless amounts of subjects. They are geared towards the general audience and serve as a point of access to the internet. Google, Yahoo!, MSN and the Chinese Baidu are among the most frequented internet portals.³⁾

• Vertical Portals: Also referred to as Vortal, a vertical portal aggregates information concerning a specific subject or interest area, market or industry. It is geared towards a specialized online community or interest group.⁴⁾

• Intranet Portals: Many major companies run their own intranet portals. Exclusive to their employees they serve as point of access to knowledge and data concerning the company and its business. While on the surface intranet portals might resemble horizontal portals (offering functions such as news, stock-exchange information, keyword search), major differences are the restriction to company-relevant content, and the restriction of information to specific groups among the users. ⁵⁾

• Distributed Web Portals: An aggregator of information from multiple other portals in one new space. For example a hotel guide for all Germany might aggregate its information by pulling and combining information from various local and city-specific hotel guide websites. A distributed web portal does not create new functions or level of information by combining different sources - it only collects and displays information that is already available from other sources.⁶⁾

• Others: Due to the broad definition of the term the typology above can not cover all variants of existing portals. Youtube for example can be considered a hybrid of horizontal and vertical portal. It aggregates information on an endless number of subjects, accessible through a keyword search engine, but the information is restricted almost exclusively to audiovisual content. Hence one could argue that it is geared towards a specific interest group: users with an interest in audiovisual content. An online community like Facebook could be considered a portal as well, as it acts as an aggregator of information and links to a broad variety of web content. Unlike horizontal portals the content is being aggregated by the users themselves. By restricting content to a community and further to specific groups within that community (a users friends) it has characteristics of vertical and intranet portals.

According to current statistics the five most frequented websites are:

1. Google.com
2. Facebook
3. Youtube
4. Yahoo.com
5. Baidu.com

Out of the 25 most frequented websites 9 are Google and Yahoo! domains (seven country versions of Google, two of Yahoo!). Together with MSN, Russian Yandex, Chinese Baidu and QQ internet portals make up more than half of the world’s 25 most frequented websites.⁷⁾

Google is the most frequented internet portal. By mid 2009 it accounted for 81% of all internet searches worldwide.⁸⁾ Established as a company in 1998 Google developed around a new search engine algorithm first made available in 1995 under the name BackRub.⁹⁾ While the search engine is still central to Google’s identity, the company has developed numerous and extensive other functions and applications.

Google supports more than 104 languages and dialects and offers a special country version for more than 115 countries. Fortune Magazine listed Google as #2 of its The World's Most Admired Companies ranking of 2011, topped only by Apple.¹⁰⁾

For the fiscal year of 2010 Google reported a total revenue of 29,321 million USD. More then 96% of this revenue is derived from Google's advertising programs.^{11) 12)} Google's major advertising programs are the keyword-advertising Google AdWords and the ad-placement-network Google AdSense.¹³⁾

Established as a company in 1995 Yahoo! developed around a structured list of web links started by two Stanford students as a navigation tool for the internet. The company quickly became one of the worlds most recognized internet brands.¹⁴⁾

Yahoo! established a major following by offering useful and free-of-charge services to its users. Yahoo! Mail, launched in 1997, is the second biggest online email provider with approximately 310 million users. ¹⁵⁾ Further services include Yahoo! Messenger and the photo sharing side Flickr with approximately 51 million registered members.¹⁶⁾

For the fiscal year of 2010 Yahoo! reported a total revenue of 6,324 million USD. 84% of this is derived from advertising income, which can be separated in display advertising on Yahoo! network pages (34% of total revenue) and search advertising on Yahoo! network pages (50% of total revenue).¹⁷⁾

Portals are central to how the internet is being conceived by users today. In a vast and ever growing jungle of content they offer a point of reference, guidance and prioritization. This applies particularly to the major internet portals such as Google and Yahoo!, which have developed into economic giants. ¹⁸⁾ In 2011 Google and Yahoo! took a combined share of 52% of all money spend on online advertising in the US, while Facebook accounted for only 7%.¹⁹⁾