Yeah...that tweet could mean any number of things.
They could be moving the website over. That would be...possibly pointless? Not sure the advantages. Maybe they'd be moving the code base over somehow?
Maybe he actually meant he's moving the developers over?
Or he could be talking about actually starting to do a merger with Steem and Tron, where Steemit somehow works on both networks.
Maybe the confusion alone was why he deleted it.
Maybe he'll clear it up with a longer explanation later.
Not quite time to panic...yet.