We need a hipster name filled with irony and lacking vowels.
"re" doesn't work for me. Tweet -> tweets, tweeted, tweeting... re -> res, red, reing - not friendly or obvious words. "Sub" is too like subreddit. Maybe "ping", like sub => submarine => sonar => ping, or "step", like the way down to the basement, which also ties in visually with the post structure.
How about a lev? Hey, are you on my lev? You find that lev? First lev! YES IT MUST HAVE THE BREVE ( V ) ;)
When did 'Post' go out of fashion?