Derek Sivers explains in a 3 min TED talk, <a href="http://www.ted.com/talks/derek_sivers_keep_your_goals_to_yourself.html" rel="nofollow">http://www.ted.com/talks/derek_sivers_keep_your_goals_to_you...</a>, that by keeping your goals to yourself, you become more motivated to achieve them (because you haven't made them part of your "social reality"). In the very early stages I suspect that might be the biggest benefit of stealth mode..