What exactly is a "juice link"

Does anyone have any good idea what long tail pro's definition of a "juice link" is? Would a expired web 2.0 be one? an aged domain?


I noticed long tails keyword competitiveness differs greatly from country to country ip address im using.

If i wanted to primarily rank "yorkshire terrier puppies" in google.co.uk would it be best to buy a .co.uk domain rather than .com?