Safari 4 comes with a slew of cool new features, but extensive data generation combined with poor cleanup make for a data trail that’s a privacy nightmare.

Hidden files with screenshots of your history, files that point back to Web pages you’ve visited and cleared from your history, and thousands of XML files that track the changes in the pages in your Top Sites can add up to gigabytes of information you didn’t know was kept about you.” Some of Safari’s bloat is kept in quite obscure locations; it takes a fairly knowledgeable user to find it and clean it up. You can avoid some of the worst of it by disabling Top Sites.