According to Glass support Twitter is no longer developing their Glass app. This was one of my favorite and most used apps on Glass. If you remove Twitter from your Glass it disappears from Glassware and there is no option to reinstall it.
The Twitter app has also disappeared from MyGlass, Google Glass's management and app center. As 9to5Google noted, in the past, opening the app would spur the message, "If you have Glass and want to start using Twitter, simply go to google.com/myglass and turn on Twitter." This message has disappeared. Once a user deletes the app, they cannot reinstall it.
Twitter might not be dead and gone from Glass completely, as a third party app developer could swoop in to fill the void. Still, this is a hit to Glass's ego. As one Redditor put it, "This is bad news, not because of what it says but because of what it implies—that the interest in Glass from major players like Twitter is decreasing, before Glass is even released to consumers."