<p>There are some good answers here. My policy (and I think the default overall), is that if I edit, I remove all peripheral comments, be they 'thanks', '-Bob', 'I'm not a statistician, sorry about the dumb question...', etc.  </p>

<p>A topic that hasn't been covered much yet is deciding <em>when</em> to edit, or to approve suggested edits.  </p>

<ul>
<li>If the only thing that needs to be done is remove 'thanks', I won't edit so as not to bump the thread.  If someone else has suggested an edit that only removes 'thanks', I click <code>reject</code> as 'too minor'.  </li>
<li>I am slightly more likely to edit (approve) to remove only '-Bob' or 'I'm not a statistician...', but the older the thread is, the more likely I am to leave it.  </li>
<li><p>The more of such stuff there is, the more likely I am to edit.  </p></li>
<li><p>If I edit for whatever reason, I will always remove this sort of thing as well.  If I review a suggested edit in which these have been left in, I will click <code>improve</code> and remove them before approving.  </p></li>
</ul>
