How to determine the real link popularity

[wll6568]

It seems like marketleap tool reports backlinks a lot higher than the actual backlinks Google counts. For example, if I query a site at marketleap, it shows 12500 backlinks from Google, but then when i query at google with link:www.site.com command, it shows 3380. Why is that? Does anyone know?

[ken_b]

when i query at google with link:www.site.com command,

Google only shows you a sample of the links they know about. The number of links shown may not be anywhere close to the number of links Google is actually aware of.