The tweet was discovered by Jonathan Gottfried. The latter made the first unofficial Twitter client for Glass called "GlassTweet". The main question, which will remain unanswered until the consumer version of Glass is released, is what exactly will you be able to do using a Twitter app on Google Glass? Certainly the limitations of the device prevent you from having the full capabilities found on the Twitter for Android app.
Still, seeing that Twitter is working on the app does seem to make the point that this is a product that will be in consumers' hands before you know it, ushering in the real start of wearable computing. Watch for more apps to be created for Google Glass over the summer.
source: TwitterforGlass via TechCrunch, AndroidCentral