CoLT (short for “Copy Link Text”) makes it easy to copy either a link’s text, or both the link text and its URL in a format you specify. This non-invasive extension simply appears as context menu items when you right-click a link. Fully customizable!
Here is a little more about the add-on from the developers:
CoLT adds two menu items to the browser’s context menu, both of which are only visible when right-clicking a hyperlink. The “Copy Link Text” menu item copies a hyperlink’s associated text to the clipboard, while the “Copy Link Text and Location” menu item copies both the hyperlink’s text and URL to the clipboard in the format you choose: either as plain text, as an HTML hyperlink, or as a custom format (which you may specify). A very handy tool for blogs!
Interested in learning more? You can download CoLT for Firefox from the Firefox Add-ons website.