From Adobe Systems:
Watchfire WebXACT is a free online service that lets you test single pages of Web content for quality, accessibility, and privacy issues.
The WebXACT extension provides an interface to the Watchfire WebXACT online service that lets you test the content of Web pages in Adobe GoLive CS.
Note: WebXACT is an online service. The Web page must be located on a publicly available Web page that the WebXACT service can access.