Pasteboard is a simple application that just gives you a 10-page notebook to keep text you might need while you're copying and pasting. It doesn't do anything particularly clever, just serves as a save, lightweight place to keep text.
Windows' Clipboard may be useful, but it's limited. There are programs that expand that function, like M8 Multi Clipboard, but they can sometimes be more hassle than they're worth. Pasteboard sits in between these two poles, resembling a ten-page notepad where you can dump whatever text you like.
Pasteboard only accepts text, but it doesn't need installing, so you can run it from a USB stick. It just features ten tabs along the top of the text window, and you can store whatever text you want in them. The content is automatically saved by Pasteboard, so you can be sure of not losing anything.
If you're looking for a simple app where you can store text while you're working, Pasteboard is a good solution. Be aware that it's extremely basic and doesn't save images or files.