The opposite of a portal (in my mind) is a mashup (of various external interfaces or "gadgets" as you suggest). Moreover, the absolute polar opposite would have to be a client-driven mashup where the viewer selects which "gadgets" he or she needs.

Google's customizable start page demonstrates this very well (you can easily use 3rd party gadgets adhering to an api) accept you need to sign-in and the configuration data is stored on google servers instead of locally (on the client computer).

The shortcoming of mashing gadgets (3rd party) together on a page is that, at this time, there is no standard means of allowing the gadgets to intercommunicate on a page (events) and few means to actually mash gadgets together without tenuous (unsupported) hacks.

Rein