Eran Hammer-Lahav blogs about an important principle behind OpenID, Yadis, OAuth and a number of related technologies that he calls the "Equal Access Principle". He says the requirements are:
Support large and small providers. Any solution must work for a small hosted website as well as the world largest portal. It must be flexible enough to allow developers with restricted access to the full HTTP protocol (such as limited access to request headers) to be able to both provide and consume …
I call this the Equal Access Principle. The principal, simply put, asks protocol designers not to be snobs. It states that protocols should be able to operate not only on the most powerful frameworks, but within the constraints of the limited frameworks which are part of the web reality. It is a sort of socialism for protocol architecture. We take away some power from the top to make sure those closer to the bottom can also play along.
I like the term, and I particularly like that he’s giving that important architectural principle a name. Obviously, I like the concepts behind it, too ;-) Isn’t perhaps the main reason for the phenomenal success of the web exactly that principle, that big guys and little guys can play on a level ground? It’s important to keep that in mind…