Interclue

Interclue is a Mozilla Firefox extension that lets you check out a preview of the links on any website before you open them.

This is a great way to avoid opening unnecessary pages – especially useful when you already have a lot of tabs open and don't want to add any more to the list.

Interclue not only lets you preview a thumbnail for any of the links on a webpage, but also shows you extra info about its content. You can even do certain actions like sending the content via a link in an email, adding it as a bookmark, or copying it to your Windows clipboard.

To open the Interclue window, just hover your cursor over the icon that appears next to every link and wait a few seconds.