Google, in their Webmaster Central Blog, has introduced a nice little feature to the webmaster tools interface recently. The new feature identifies source URL’s for various errors that they detect.
For instance, when they display a 404 (not found) error for your site with a link to the missing page, now they will also tell you where they found the link to this error. This added feature can save a webmaster a ton of time in some cases.
While there are other tools out there such as Xenu Link Sleuth, to help detect broken links, this added feature in Google gives site owners one more tool to help troubleshoot a website. The tool will display the source of all URL’s causing any errors that Google reports.
In Google’s “Not Found” and “Errors in URL’s in Sitemaps” sections, you will now notice a “Linked From” column.
While this addition is not a major breakthrough, it does show that Google is actually listening to its users, and does increase the usefulness of Webmaster Tools. (On a side note I found it interesting that in Google’s own screenshots, they had 258 “Not Found” errors - I would have expected a few less.)