I disagree. There is always something to be learned from Stackoverflow. It is impossible that 1 person has the same knowledge of all the users on the site. There are very interesting questions and answers.
Are there allot of simple questions? Yes because there are many people just learning how to do basic things in one language or another. However even in the most basic question answering it can be an worthwhile experience. You can filter out the simple questions and get on to the more advance ones pretty easy.
Most start ups fails because the passion for the company fades because of the work involved. If you have the "safety net" of welfare then you might not be willing to put in that extra 3 hours to keep your company afloat every night.
If you haven't taken the time yet you should read the Copilot spec. It caused me to rethink how specs should be written, and what is the right level of detail.