You probably already know this (we know you're very smart!), but it bears repeating: your browser saves a whole lot of data about what you do. Beyond just your browser history, the most visible trail of what you do on your PC, there is also your browser cache and cookies. Cookies are used by websites to keep you logged in and to track your browsing habits to provide targeted advertisements, while cache saves sites (or parts of sites) on your computer to speed up your browsing. But they also leave telltale signs of your Facebook addiction and predilection for the most exotic flavors of pornography. To cover your tracks, even if it's just to keep a nosy spouse from discovering what you're planning for your anniversary, you'll need to clear out this data on a regular basis. The process is slightly different for each browser, but here's a quick how-to for all of the major competitors in the field.
Click on the "Tools" in the menu bar (you may have to press Alt to reveal the menu bar) and select "Delete Browsing History." Check the boxes next to "Temporary Internet Files," "Cookies" and "History" then click "Delete."
Click on "Tools" in the menu bar and select "Clear RecentHistory." Unlike Internet Explorer, Firefox lets you choose how far back you want your house cleaning to go. After selecting the time range, click on the arrow next to "Details" and make sure the boxes next to "Cache," "Cookies" and "Browsing & Download History" are checked before clicking on Clear now."
Click on the wrench icon in the upper right-hand corner and select "Clear Browsing Data" from the "Tools" menu. Make sure the boxes next to "Clear Browsing History," "Clear Download History," "Empty The Cache" and "Delete Cookies and Other Site Data" are checked, and choose a time frame to delete the data for from the drop-down menu. When all is set, click "Clear Browsing History."
Clearing the cache in Safari is as simple as selecting "Empty Cache" from the Safari menu. If you want to clear out other data, though, you'll have to select "Reset Safari" from the same drop-down, and check the boxes next to "Clear History," "Empty the Cache," "Clear the Downloads Window" and "Remove All Cookies" before clicking "Reset."