Mac OS X only: You already know you can select text in any application on your Mac and drag it to the Desktop to create an instant file with its contents in it. The MacTipper Blog takes saving text snippets to the next level with the Clipper service, which sends text to a file saved in a “Notes” folder in your home directory. Download Clipper and save it to
~/Library/Services/ (you may need to create that directory, I did), and log out and back into your Mac. Then, from any Cocoa application, you can select Clipper from the Services menu to save selected text to Spotlight-friendly, dated plain text file. This method is slightly better than the drag-and-drop approach because you can assign a keyboard shortcut to it; but it does not work with Firefox (Clipper is grayed out), which is a huge bummer. Clipper is a free download for Mac only.