http://drupal.org/project/search_and_replace
This is a really simple module but it's to help alleviate a really annoying problem: referencing material that is date sensitive or has changed in terminology. This module will allow you to perform a search and replace across all your drupal content based on content type and perform a replace. This can get REALLY taxing on your system if you have a ton of content so be careful with it. After submitting the request it will tell you how many replacements were made and what pages the replacements were made on. Currently only scans body text but future plans are to scan other fields such as CCK and Title fields.
Use case: You accidently refer to everything in your online material as "the instructor's blog" and realize that later on in your content you started calling it "the instructor's wiki-site" because you changed to a wiki from a blog. Perform your search for the phrase and replace on your site and you no longer have to hunt through the content for it or do a search and then replace by hand.
The most common use case for us is dates that change semester to semester or syllabi that's included in the content itself. This lets us find dates such as due dates just by finding one or two that are incorrect and then performing a massive search and replace to catch all of the buggers. There will be someone else working on this with me so please feel free to include feature requests on the issues queue cause this project just started....yesterday.