Nothing bad about the Twitter Inventor, but there was (A LOT) of luck involved in the success of Twitter. His next project might be interesting, but it is 99.999% certainly not a new blockbuster like Twitter.
I'm not sure we can even call it a success yet. It's certainly getting popular, but in terms of ROI? Well, we'll have to wait and see if it generates any revenue.
Making something people want is great, but it's only half the battle. You have to be able to translate that into something they want that you can make money from. Twitter hasn't shown they have any clue how to do that yet.