A Web Page which acts as information gateway and has user-customized destinations and/or content. A portal can be thought of as an assortment of magic mirrors on a wall that display far away places and things. The mirrors are on a Web Page displaying information locally or remote and can be rearranged and altered for relevance and use.
The trick of the portal is to provide key information ingredients most optimally: the right amount of information to a given person at the right time in the way they want it.
List of web sites with portals: This list is not exhaustive.