Dear Tumblr: I want my post summary!
If {PostSummary} and/or {PostTitle} theme variables worked inside {block:Posts} I could do something like this:
<a href="http://twitter.com/share" class="twitter-share-button" data-url="{Permalink}"{block:PostSummary}data-text="{PostSummary}"{/block:PostSummary}data-count="none"data-via="sdowding">Tweet</a><script type="text/javascript" src="http://platform.twitter.com/widgets.js"></script>
Tumblr, please make my life easier!