I'm hoping that when Marco says "I've sold a majority stake" he doesn't mean "I've sold everything". I'm a big Instapaper fan, and I'd hate to see someone else take over deciding the direction the service should move in.
A big part of Instapaper's success comes from the fact that Marco's done a great job at steering the ship. He really is a world-class product guy who knows what to say no to.
Congratulations to Marco and Betaworks. I hope it works out well for all of us.