Lupus -
Thanks for the reply and thanks for the content management info. Requirements management is a little different than content management. Requirements define the functionality for your site or system. Content is the information stored in your site or system. The tools to manage each are a little different.
A requirements management tool helps you gather, organize, trace and track the requirements for your site. For example, if you have a search page that has a keyword search field, one requirement for that page could be stated as "The page will provide a keyword search mechanism. The mechanism will support wildcard searches and comma delimited search items.".
Tracking requirements is useful for a variety of reasons. First, it helps you plan and manage the scope of your project. Second, it's vital in creating your test cases. Every requirement needs to be tested (i.e., test case). Third, it's useful to track the evolution of your requirements. If a requirement changes, it's nice to know what the requirement used to be.
A spreadsheet could do; however, I'm sure there are affordable requirements management tools out there that are a little more streamlined and geared towards web development.
Thanks again.
ps - 13, huh? Keep it up!