The idea of telling readers that your site has been updated is far from new. Back in the mid 90s, practically every Web site carried a date in the footer that proudly proclaimed, "This page was last updated on...." But that nod to transparency carried with it two inherent problems: first, it was rarely an accurate indication of when the site had last changed, and second, readers had no idea how the site content had been revised.

Versionista offers a modern version of that update notice that alleviates both of those problems. It provides both an accurate date of the last change and reveals the edits that have been made between versions of the site - highlighting what has been added and removed in side-by-side comparisons.

Why reveal this information? Because not revealing it can be used against you. Versionista rose to fame on the campaign trail in 2008 when United States Presidential hopeful John McCain used the tool to highlight changes Barack Obama's team was making to its Web site. While the content on your site might not be under as much scrutiny as that one, it's always better to be as transparent as possible.

Adding the change log feature to your site is simple. Register for Versionista, begin tracking your site, and then add a snippet of javascript to your pages. When you make changes to your site, visitors will see the date of the last update and will be given the option to click through and compare the current version to past versions.

While this sort of transparency isn't for everyone, it offers yet another way to be open and honest with visitors to your site. And remember, even if you don't add the feature there's always the possibility that someone is using Versionista to watch your pages for changes, anyway.