Back in the day, when life was hard, we had to mark up pages using notepad and we absolutely positively had to make them viewable within an 800 X 600 resolution. But you try and tell the kids that these days and they just won't believe a word you say.

Not a word...

So back in 2000 the broad screen resolution breakdown for web users looked something like this:

courtesy: www.thecounter.com

Therefore you as a web developer were incentivised to develop to the 800 X 600 resolution (I actually remember the discussion about moving up to 800 X 600 from 640 X 480).

Now-a-days it's much different:

courtesy: www.thecounter.com

It's just interesting now and again to revisit accelerating change.  Bottom line, if you are still basing your design on 800 X 600 you are not using the available screen real estate fully.

Update: and taking a look at my google analytics it is even more striking.