It depends on the context. Was this a citation on the Tarsnap article? If so you just saying something publicly is a good a source as any, it doesn't matter that the publishing platform is Twitter or the New York Times.

Actually Twitter can be a much better source than an accredited newspaper, because in this case it would be coming directly from you, and you wouldn't need to worry that perhaps the source was being paraphrased, or the context wasn't what they intended.