what is a horizontal and vertical portal?

A horizontal portal covers many areas. It can be used as a platform for multiple social and collaborative purposes. It can also be used by more than one company in the same industry. Liferay Portal is a horizontal portal, because it has a collaborative suite of blogs, wiki, mail, and calendar
portlets. Its message board and chat portlets can be used for social activities.

Ex: Yahoo  portal / sute (Yahoo.com)







A vertical portal focuses on one functional area. It is a specialized entry point to a specific
market, industry, or subject area.

Ex: You Tube