what does external juice passing links mean ??

I am sure somebody can explain this? 

Is a site A links to your site with a link that is dofollow, then the link on site A is a juice passing link for your site.

Do Follow: It is a tag used in HTML code to tell search engines that a link put up on a site is a link that is recommneded by the owner on whose site the link appears.

Do some Googling and you will learn more about it. 

Thanks Ranjith that was very explained in very simple in words .. and i think i should be working on it ... merry christmas and happy new year in advance you.

Thank you and wish you the same