<p>Very common for PhD students to drop out. Less common for master's students--it's a short program. But the value of an MS in CS is, as I understand it, dubious. Plus master's students often get stiffed on funding.</p>
<p>Here at Harvard, it seems like everyone in the CS department and their dog has, or is starting, a company. An MBA or a master's might help, but you could also use that cash for seed money...you certainly don't <em>need</em> a graduate (or even an undergraduate) degree to start a business.</p>