A former Twitter engineer has released an app that lets you schedule your tweets to be deleted. Enable Spirit for Twitter and append a hashtag like #1m, #2h, or #3d, and your tweet will disappear after the specified timeframe. It's introducing even more ephemerality to a service that's already heavily focused on the moment.

Besides keeping your digital detritus to a minimum, there may be practical uses for the app. One meteorologist has already found a neat use for it: preventing storm warnings from being retweeted once they're no longer in place. Spirit follows Efemr, another app with the same functionality.

While allowing tweets to expire may seem to undermine Twitter's bottom line — collecting data that can be advertised against — the company is still allowing both apps access to its API for now.