Apparently Michael Tsai doesn’t like the data detectors feature in Leopard. Personally I love it. For those of you who don’t know, data detectors is a feature that adds smart links to chunks of text based on what it thinks the text describes. For example, one feature that I use all the time in Mail is the detector that turns any date or time into a link allowing you to add it to iCal as an event.
The really neat thing about it is how it can scan the entire post to come up with information to fill in about the event – even looking at different regions of text scattered throughout a mail. It’s pretty neat and is exactly the type of thing that Wil Shipley is talking about here when he mentions adding features to your apps that constantly surprise users in a good way (I’ve seen designers from BMW talk about the same thing in the context of styling their car interiors).