When you turn on your Mac, various apps, add-ons (such as menu extras), and invisible background processes open by themselves. Usually these automated actions are exactly what you want, but you may sometimes see items running--either visibly or according to a listing in Activity Monitor (located in /Applications/Utilities)--that you don't recall adding yourself. Where do they come from? Because such items can increase your Mac's startup time (and may decrease its performance), you'll want your machine to load only items that are useful to you. Here's a quick primer on the various kinds of startup and login items and how to manage them.
