user2: For example, this question is one that I would consider on topic for this site. However, it's already been answered on the homebrewing site.
Normally I would say let the both questions exist and have them get answers from the perspective of the site they're on, meaning that on here the answer would be only about the specifics of the beer(s) themselves and on the Homebrewing site it'd be from the perspective of making the beer. In this specific case, it's a little bit weirder since the accepted homebrewing answer isn't even relevant to homebrewing (but I may be wrong about that).
What should we do in these situations?

user39: Nothing. 
While it's unfortunate to have duplicated information across sites, sites that have overlap in topic should not be afraid to have some overlap in questions. If it's clearly on topic in both places it's not an issue.
My guess is that homebrew has been housing a lot of questions that would be borderline off topic if they had a site to ship them to, if this site does well that will give them a good opportunity to focus on the brewing side rather than the tasting/history side.

user13: 
What should we do in these situations?

Nothing. They're two different sites with different (but overlapping) audiences. In this specific situation, the exact same question (and its answers!) would be appropriate on both sites, but there'll be plenty of cases where that won't be true, where the needs of a brewer and an enthusiast overlap but don't align perfectly. 
Generally-speaking, Stack Exchange sites are expected to stand on their own, catering to their own communities and being a bit jealous of their questions - there's no such thing as a cross-site duplicate. 
That said, there are two things worth keeping in mind, particularly early on:

If you're pulling relevant information from a different site, don't forget to attribute it properly. Ideally, there'll be cross-links between sites with related topics, with overlapping expertise aiding readers on both.
Don't post identical questions on both sites, and be very careful about re-posting questions that've already been asked elsewhere. It's important that we establish a clear role for this site during the private and early public betas; if the questions here are too close to what's available elsewhere, it'll make it harder for future members to recognize what is and isn't on-topic. Focus on identifying areas where the good folks here weren't being served, and make sure the answers they're receiving are fresh draughts. 


2: <p>For example, <a href="https://alcohol.stackexchange.com/questions/25/what-specific-characteristics-distinguish-an-imperial-stout-from-other-kinds-of">this question</a> is one that I would consider on topic for this site. However, it's already been <a href="https://homebrew.stackexchange.com/questions/949/what-does-imperial-mean-with-regards-to-beer-style">answered on the homebrewing site</a>.</p>

<p>Normally I would say let the both questions exist and have them get answers from the perspective of the site they're on, meaning that on here the answer would be only about the specifics of the beer(s) themselves and on the Homebrewing site it'd be from the perspective of making the beer. In this specific case, it's a little bit weirder since the accepted homebrewing answer isn't even relevant to homebrewing (but I may be wrong about that).</p>

<p>What should we do in these situations?</p>
 39: <p>Nothing. </p>

<p>While it's unfortunate to have duplicated information across sites, sites that have overlap in topic should not be afraid to have some overlap in questions. If it's clearly on topic in both places it's not an issue.</p>

<p>My guess is that homebrew has been housing <em>a lot</em> of questions that would be borderline off topic if they had a site to ship them to, if this site does well that will give them a good opportunity to focus on the brewing side rather than the tasting/history side.</p>
 13: <blockquote>
  <p>What should we do in these situations?</p>
</blockquote>

<p>Nothing. They're two different sites <a href="https://homebrew.meta.stackexchange.com/questions/344/what-do-you-think-about-launching-a-separate-site-for-beer-appreciation">with different (but overlapping) audiences</a>. In this specific situation, the exact same question (and its answers!) would be appropriate on <em>both</em> sites, but there'll be plenty of cases where that won't be true, where the needs of a brewer and an enthusiast overlap but don't align perfectly. </p>

<p>Generally-speaking, Stack Exchange sites are expected to stand on their own, catering to their own communities and <a href="http://blog.stackoverflow.com/2012/03/respect-the-community-your-own-and-others/">being a bit jealous of their questions</a> - there's no such thing as a cross-site duplicate. </p>

<p>That said, there are two things worth keeping in mind, particularly early on:</p>

<ol>
<li><p>If you're pulling relevant information from a different site, <a href="http://blog.stackoverflow.com/2009/06/attribution-required/">don't forget to attribute it properly</a>. Ideally, there'll be cross-links between sites with related topics, with overlapping expertise aiding readers on both.</p></li>
<li><p><a href="https://meta.stackexchange.com/questions/64068/is-cross-posting-a-question-on-multiple-stack-exchange-sites-permitted-if-the-qu?lq=1">Don't post identical questions on <em>both</em> sites</a>, and be very careful about re-posting questions that've already been asked elsewhere. It's important that we establish a clear role for this site during the private and early public betas; if the questions here are too close to what's available elsewhere, it'll make it harder for future members to recognize what is and isn't on-topic. Focus on identifying areas where the good folks here <em>weren't</em> being served, and make sure the answers they're receiving are fresh draughts. </p></li>
</ol>
