Just finished fineprint which is a jquery plugin that let’s the developer direct the user’s attention towards small fragments of your very large document. It’s easily customizable and let’s you drop it on an already functional page, being truly unobtrusive.
fineprint adapts to your text and displays the larger text excerpt a little bit longer. It also allows you to customize the CSS of the highlighted text. Plus, it is compatible with jQuery UI's effect highlight.
The project is up and running on github: https://github.com/chelmertz/fineprint which includes full source, documentation in form of an API and a couple of demos.