@coda: I agree. KISS Should be the pursuit of any interaction designer designing for the masses.

@Vocable: I guess it depends on whether there is animation present or not. If pressing down, and it looks like the whole tumbler rotates down, then I guess it would be learned quite quickly.
People are not alike, some like inverted mice (for example), others insist it goes the ‘right’ way. I’ll see what I can find about such studies.

“One could also capture the Arrow keys. If the down arrow was used, the date could increment up by each keystroke.”

I think that making use of the arrow keys is an excellent idea in general and should be standard practice for these sorts of controls, but…this is a case where the customary use of arrow keys could be confusing.

While in the interface it makes perfect sense for a down gesture to increment the field values up, would that be intuitive for someone using the keyboard? I feel like once those fingers hit the keys the user will expect an up arrow key press to increment the date up one day/month/year. I have been thinking about this very usability issue a lot lately in reference to interfaces I am working on. Do you (or anybody out there in internetland) know of any usability studies in this area?

Dates are always important data so I prefer a KISS approach that is fool-proof and backwards-compatible: individual select fields for Day, Month and Year. Click on the field, and scroll to select. I’d probably reconsider this approach when working with multiple dates though (thinking Google Analytics, which I love – no idea how it downgrades though).

Ultimately it depends on the context: date type, target audience, technical requirements (browser support), etc.

Also with predefined dates. Date of Birth for example – I find if you know your audience then you can calculate an average birth year, but even that might be risky when older users are concerned (they might take offence? people are weird about age).

Would like to see your idea implemented.

Drips & Drabs – I can identify! How long before you strip it all out and start over again? ;)

Are you using wireframes before you start your CSS / HTML work?

Ciao,
Shaun