I recently came across an elegant demonstration for getting the user to specify a preference by offering examples to choose from. This technique is often done with visual settings (e.g., letting a user select a template for a document by clicking on sample template thumbnails), but in this case, the technique was applied in letting a user specify a simple textual setting for a date format.
I've been looking at some web sites that help manage To Do lists, including tadalists.com, rememberthemilk.com, and mypimp.com. (Where do they get these names? The latter could adopt the slogan, "We think having a borderline offensive name is so funny it's worth giving up market share!") All these sites strive to be as interactive as possible, and to some extent they each struggle with the absence of conventions for entering data on highly interactive web pages. This has produced some interesting and creative UI experiments, some of which succeed.
One bit of creativity (albeit in a non-interactive area) shows up in the account setup page for rememberthemilk.com:
It's the last line that caught my attention. The label for the radio buttons doesn't even say what you're picking (preferred date format), but it's obvious what you're supposed to do: pick the sample that shows the date the way you like it. What's particularly interesting is that this trick capitalizes on a person's ability to recognize patterns at a subconscious level. I live in a country where the month comes before the date, so the first option ("14/02/05") looks like a jumble of numbers to me, while the second option ("02/14/05") leaps off the page as a valid date. Presumably people who live in date-first countries have the opposite reaction.
It may turn out that this trick only works in narrowly constrained circumstances; perhaps it would stop working, for example, if they needed to support a broader range of date formats. Nevertheless, it's impressive that rememberthemilk is able to ask for something as mundane as a date format in a manner consistent with the site's overall casual visual and textual tone.