<p>To answer your direct question: nope, comments are not searchable (currently) by the in-house search feature. I believe Google looks at <em>all</em> text on the page, including comments, but there isn't a way to limit searching to comments only.</p>

<p>That said, if your SQL is pretty good, you can use <a href="http://data.stackexchange.com" rel="nofollow">Data.SE</a> and search comment text for any graduated site.</p>
