Interesting Difference in Google Backlinks

Why does putting a space between link: and www differ.

[Jack_Frost]

When checking backlinks in Google for a company, I get drastically different results if I type in link:www.xyz.com (usually a very low number) and link:(space)www.xyz.com (what appears to be every link that they actually have.) The difference is huge!

I suppose the first one represents the more important links that Google is weighting more heavily in its formula and that the other one represents every link that they have (decent or worthless). I wonder if there has been discussion on this point before.

[Philosopher]

Actually

link:www.example.com

does an actual backlink check where as

link: www.example.com

does a search for pages containing the terms "link" and "www.example.com" not an actual backlink check.

Often the the second will return pages that do link back, but only if they display the actual url on the page.