Bartender is a Mac app that manages items in the menu bar. Up until the release of the Mac App Store mine had only Caffeine and Dropbox icons in addition to the stock Airport, volume, battery, and date. Since then, hanging things from the menu bar has come into fashion. For better or worse, many apps place a menu bar icon for constant access and monitoring. Bartender collapses the running menu bar items into its own icon, greatly reducing the clutter.
Now, just Bartender and Dropbox show and everything is a little cleaner. You can test it while it’s in beta for free, and if you purchase a license before the 1.0 ships, they are offering a 50% discount.