Today’s, "Hmmm. I never thought of that, but it makes sense," moment comes courtesy of Infectious Greed. Author Paul Kedrosky suggests that you can tell a software product or service has come of age when it gets an undo feature.
He points out that many products start out with no undo feature, primarily because early adopters are used to technology that breaks or makes mistakes.
Perhaps it would be more accurate to suggest that most early adopters don’t use cutting edge computer services or products for things that are important enough to require an ability to undo actions.
Either way, it is an interesting way to look at it. More importantly, it gives users a quick, one-step, method to determine the relative maturity of a particular product without being required to base such analysis on easily manipulated things like version numbers.