<p><a href="http://en.wikipedia.org/wiki/Progressive_enhancement" rel="nofollow noreferrer">Progressive Enhancement</a> is a web development methodology that not only allows greater portability and accessibility but in my opinion, makes the development process easier.</p>

<p>What I want is to know what the rest of the community think of this approach.</p>

<p>In particular: What do you believe is the minimum set of technologies that a web application should support?</p>

I personally block referrers, cookies and JavaScript by default and re-enable them temporarily or permanently on a site-by-site basis.
I'll forgive a web site for not working without cookies for signed-in users, however I get quite upset when they won't work without JavaScript if it's being used for trivial purposes.
Minimum requirements: HTML with basic structural elements + links, HTML forms + maybe cookies for applications.
Site could be run in a vt100, a "normal" browser, a phone, a screen reader...
-z