<p>My thoughts:</p>

<ol>
<li><p>I agree that we should either (a) restrict to those sites or else (b) do everything but them.  The latter option would give more variety in the communities so I think that it could be more interesting, and it would give a picture of communities at much different stages of development and in completely different fields.  So we can get a nice picture of community development and decay.  </p></li>
<li><p>I don't think that we should necessarily need to sample initially based on doing step 1.  People can then engage in dimension reduction or sampling exercises as part of the actual analysis if there is too much data, although I'm optimistic that we can make available all of the data given the restriction from 1.</p></li>
<li><p>I'm happy to act as the "data tsar" to get that started (or someone else can), and post a complete dataset in a readable format (or at least provide a script to get it).  That being said, I think the data processing part of this task could be part of what someone's value add in this whole project.  So long as everyone has access to the same data (which they do already), then whether everyone <em>uses</em> the same data isn't especially important in my view.</p></li>
<li><p>Clearly what data one uses will depend on what question they're trying to address.<br>
I myself am interested in describing how the communities differ.  For that, I would probably start with basic descriptive statistics about questions, users, votes (I'm somewhat less interested in the comments and badges tables), look at some of the distributions (I'm sure that most voting patterns follow a power law, for instance).  Maybe we can use a gini coefficient to classify the inequality of the various communities.  And I would also want to look at social network relationships (e.g. connectedness)?  Is there a stagnation effect as communities grow older (we seem to casually observed this)?  Do new users behave differently than old users?  Needless to say, there are a very large number of interesting questions that can be asked of this data.  </p></li>
</ol>

<p>Alternatively, to answer the "what makes a good question/answer", <a href="http://garr.posterous.com/how-to-create-a-guaranteed-killer-ted-talk-wi" rel="nofollow">we can do something like this</a>.</p>
