This could be especially useful for creating killer screen shots for your link bait: 7. PageDiff allows to compare HTML code differences of several pages side by side: ...

"Though no private information was clearly visible nor searchable on any of the web pages, the newspaper found that teachers' Social Security numbers were contained in the HTML source code of the ...

Factoring common JSP or HTML code out of multiple pages and into a single file improves maintainability (you need to make changes in only one location) and reusability.