The clipboard in a modern operating system is one of the most useful and practical tools available. Being able to select some text or images, copy them to the clipboard, and then paste them in other places is indispensable (look at the uproar over the fact that the iPhone OS 1.0 & 2.0 did not support a clipboard to see how valuable it is). You most likely use it without giving it another thought.
The standard clipboard behavior is that when you copy a new item, it replaces the existing item. You can’t go back to the previous item as there is no history of items copied. This is what a Clipboard Manager does, providing a memory and browsing history so you can paste something, and then find it later, even after using the clipboard multiple times.
There are quite a few Clipboard Managers available for OS X, some free, some not. Here’s a quick overview of what is on offer and what they can and can’t do. Read More about 10 Clipboard Managers for OS X