Firefox only (Windows/Mac/Linux): If you've found yourself wanting for a clipboard manager you pack along with Firefox when you commute between work stations, Clipple extends clipboard functionality wherever you use Firefox.
While a system-wide clipboard manager might be ideal, if you do most of your work in Firefox and you take it with you everywhere you go on your flash drive it's efficient to plug your clipboard manager right into Firefox.
By default Clipple extends the clipboard from 1 to 15 entries, you can increase the number of entries in the settings menu as well as limit text entries by maximum number of characters. You can also instruct Clipple to ignore text manipulated in password dialogue boxes and to save the clipboard bank between Firefox sessions. It's worth noting that while the paste function of Clipple only works within Firefox it does capture text system wide — copy an entry in a .TXT list, for example, and it appears on the Clipple clipboard.
If you're looking for a clipboard manager with more features, check out Ditto, a portable Windows clipboard manager with hot-key support. You might also want to check out how to unify your clipboard across computers.
Clipple is freeware and works wherever Firefox does. Have a handy Firefox extension you're dying to share? Let's hear about it in the comments.