The Reg:

The first, most basic, skill: be able to distinguish the different versions of the web.

Web versions, 1.0 to 2.0
Version Characteristics
Web 1.0 Programming model equivalent to that of a slightly up-market 3270 terminal. Forms are filled in with the sequence: tab tab tab tab tab tab bonk.
Web 1.00001 The beginning of the rich web experience: the first ever, primitive Javascript code fragment is written. It generates an unwanted popup, and snaffles your credit card details.
Web 1.1 No visible difference from Web 1.0, apart from IE showing the text 'Javascript error' in its status bar.
Web 1.2 Standard buttons are upgraded with smart 3D-looking GIFs. These react to mouseover events by bobbing up and down politely over their drop shadows. Remember when we were excited by this sort of scriptery? (None of your CSS cleverness then.) It seems so quaint now. It makes me want to cry, thinking about the good old days of ugly web pages loading slowly.
Web 1.3 When you get to the home page of a V1.2 site with FireFox, it displays badly. When you go to a V1.3 website such as www.fdms.com with FireFox, it tells you to eff off and get IE. (These traditionalists in fact would seem to prefer it if you used IE4.) The age of 'you aren't good enough for our website' has begun, reaching full fruition at Web 1.5, see below.
Web 1.4 Basic client-side validation added. Forms are filled in with the sequence: tab tab tab tab tab What do you mean 'invalid post code' you bloody thing? The dread phrase 'next generation of 3d smileys' is encountered for the very first time.

Via Tim Bray.