Twitter and Square are both individually much more successful than any company the author founded. Plus there's no actual argument in the post so IMHO this doesn't deserve to be on the frontpage.
Plus there's no actual argument in the post
At the very minimum he points out that preparing for an IPO (Square) and doing a turnaround (Twitter) are extremely demanding.
Which is news to no one :)
Elon Musk - Tesla and SpaceX. Although he does not advise to be a ceo of both.