<p>This is something that we deal with over at <a href="http://biostar.stackexchange.com/" rel="nofollow">BioStar</a> pretty regularly. Based on that experience, I'd argue that number 3 is the right approach, for the following reasons</p>

<ul>
<li>There's going to be a fair amount of overlap between responders on the two sites</li>
<li>Bouncing people around will just lead an already confused person to become more frustrated. We want to be helping.</li>
</ul>

<p>Of course, blatantly off-topic questions should should still be nixed. For borderline questions, I'd suggest that we give them a gentle nudge towards SO if they don't get answers here. Just suggest that they may get better responses there, and most people will be happy to make the jump over to the appropriate forum.</p>
