Pingback doesn't work on my website :(

I have installed Pingback module and I have linked other posts on my websites. For this posts, pingback works perfectly but if I link an other website, Pingback doesn't work :(

Check this post on my website YouGeek.it :

http://www.yougeek.it/2009/06/firefox-70-sfondi-incredibili-del-panda-ro...

In this post, I have linked hongkiat.com but in Pingbacks-list on:

http://www.hongkiat.com/blog/70-nice-and-beautiful-firefox-wallpapers/

my website ( YouGeek.it ) doesn't appear !!!

Why ?

Help me, I am going crazy :/