As the world's leading open source portal platform, Liferay portal provides a unified web interface to the data and tools scattered across many sources. Few months ago I started to work with Liferay in order to develop an Workflow Management System. I guess I'm in the correct track by selecting the Liferay as my portal platform. :)
Personalization, Content Aggregation, Authentication are major key words associated with a portal. Let's see how to work around with them soon !!!!!