With the release of Safari 4, the default Web browser installed on Mac computers at the time of publication, Apple added several new features, including something called Top Sites. Top Sites, sometimes referred to as Top Hits, keeps track of what Web pages you view the most and displays thumbnails of those pages when you launch Safari or open a new browser window. If you do not want to use this feature, you can disable Top Hits through Safari's preferences settings.
Click on the "Safari" icon in the dock to launch the browser.
Click on the Safari menu at the top of the screen and choose "Preferences."
Go to the "General" tab at the top of the pop-up window that appears.
Switch the "New windows open with" and "New tabs open with" settings from "Top Sites" to "Home Page" or "Empty Page." This will stop Safari from displaying your top sites when you launch the browser or open a new tab.
Navigate to the "Bookmarks" tab at the top of the window.
Uncheck the box next to "Include Top Sites." This will disable the Top Sites button that appears in Safari's toolbar.