Do you have a Yahoo e-mail account? Yahoo was one of the earliest portals on the Internet. Many users are still using the e-mail service provided by Yahoo.
Go to the http://www.yahoo.com/ site. You will find Mail, Autos, Dating, Finance, Games, Health, and Jobs links there. They cover various kinds of fields and industries, as is shown in the following screenshot:
Sometimes, I like watching videos on YouTube for a break. YouTube is a well-known site for videos. Now, go to the site at http://www.youtube.com/. What do you find there? You may have found Browse, Movies, video Upload links, and advertisements. You can also create an account at the YouTube site, as shown in the following screenshot:
You can do a lot of things and get a lot of services at the Yahoo site, while do every video-related thing at the YouTube site.
The Yahoo site is a horizontal portal. It is a platform for multiple social and collaborative purposes. The YouTube site is a specialized entry point for video fans: it is a vertical portal.
A user uses an open source portal product, free of charge. He/she can modify and extend its source code. Liferay Portal is an open source portal. It is distributed under the GNU, Lesser General Public License (LGPL) (http://www.gnu.org/copyleft/lesser.html).
Liferay Portal is available in two versions: Community Edition (CE) and Enterprise Edition (EE). A client can use its community edition, free of charge. If a client wants support from Liferay, Inc., they can buy the Enterprise Edition.
You can study the source code of an open source portal to learn portal technologies (Refer to https://github.com/liferay for the source code of Liferay Portal). A commercial portal product is more expensive than the enterprise version of an open source portal. IBM WebSphere portal and Microsoft SharePoint portal are commercial portal products.
This book is based on Liferay Portal Version 6.0. We will use this CE version to illustrate the features of Liferay Portal and set up a sample website.