Delta updates save internet bandwidth

I am playing with installing fedora 11 in my netbook (lenovo ideapad s10)
After installing fedora on to netbook, I installed yum-presto using

yum install yum-presto

After that I issued yum update which downloaded delta rpm instead of actual rpms and rebuilt the actual rpms from delta rpms. Because of this I had only to download 84 MB instead of 555 MB
This is excellent for low bandwidth linux users from our country (India)