Searching your domain with "www", showing a link or not.

If the URL is valid, try visiting that page by click on the following link

[fischermx]

I have some sites for which looking for them using site:myexample.tld, shows zero links.
But for some of them, if I search on google for "www.myexample.tld" it shows a link that says :

Sorry, no information is available for the URL www.myexample.tld

If the URL is valid, try visiting that web page by clicking on the following link: www.myexample.tld

And for others only the first paragraph is shown, i.e., it does not point me or link me to the site!

What's the difference between this two presentations?

[edited by: ciml at 11:23 am (utc) on July 25, 2005]
[edit reason] No real domains in examples please. [/edit]