It's an add on for firefox. go to
https://addons.mozilla.org/en-US/firefox/addon/425
in Firefox, and install it.
Then, on any page, select a few links by dragging the mouse over them.
Right click on any of these links (or ctrl-click on a mac) to bring up the menu.
The menu should include 'linky' - hover over this to bring up the linky menu.
Select 'open selected links in tabs'
Click the button in the window that comes up to open the selected links.
See also:
How to accelerate firefox - EASY!!
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