I guess Square. Why? 1. Pivotal's business is solid, and growing. But they must feel chagrin when they can only charge consulting fees while their clients, who

I guess Square. Why? 1. Pivotal's business is solid, and growing. But they must feel chagrin when they can only charge consulting fees while their clients, whose products they helped build, are going to be creating hundred-millionaires in short order. This might persuade Pivotal to give up their future business potential in exchange for stock options to share in the goodness. This rules out Google. 2. Twitter doesn't really need more programmers. It needs to figure out how to monetize. So Twitter+Pivotal is not worth that much more than Twitter alone. 3. Square has obvious potential, proven monetizability, and the only thing holding them back from chasing the huge array of obvious opportunities is a lack of programming talent. If they go too slow, their well-funded competitors (Visa, Mastercard, PayPal, banks) may well beat them to some markets. There's definitely a first-mover advantage to getting payment devices in the hands of businesses in any given market. All this should incentivize Square to offer a large chunk of stock to Pivotal, which should incentivize Pivotal to be acquired by them.