Efemr is a new web app that posts time-limited messages to Twitter; tweets are automatically deleted after an amount of time chosen by you, the user. It’s basically an attempt to apply SnapChat’s hugely popular formula — publishing a message that will eventually “self destruct” — to Twitter, though here your messages are likely to be seen by a wider audience. After granting Efemr access to your account, you can designate the shelf life of each tweet by attaching a hashtag time limit. #5 gets you five minutes, for example, with #1h making the post visible for one hour and so on. The web app is advertised as a means of making your Twitter activity more fleeting, but also as a tool to “protect your e-reputation.” That latter point is somewhat questionable, since all it takes is a retweet to ruin any attempt to cover your tracks on the popular service.