Tweetability lets you indicate, with a shortcode, tweetable text in your posts that your readers can tweet with a single click. As seen on nytimes.com
Simply place [tweetability]your content here[/tweetability] in your posts/pages. The text between [tweetability] shortcode would be wrapped in a special clickable block that user can click and it will open users' twitter page to tweet that text.
You can set the following values in options page or use the attribute to override the values from options page:
[tweetability via="kashiif" related="wordpress" linkclass="hilight" tooltip="Click here to tweet this instantaneously"]your content here[/tweetability]