Recently I discovered that Twitter username's have a 15 character limit. It just one of those things you did not know or note. It makes sense given that Twitter wants you to say what you have to in 140 characters. A reply to @twitterusername(a name that just made its 15 character limit) takes up 16 characters of the 140, the Twitter limit for posts.
I searched to confirm, and a writer at "The Curious Engineer" confirmed by my new finding.
Goes to the truth that you learn everyday.
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