One more step from facebook developers to save their users from application requests spam. After famous ignore-all and block-all application invitation scripts, now you can block all application invitation from specific friends.
We’ve heard from developers and users that they feel certain friends seem to be a large source of unwanted application requests. So with this change we wanted to give users the opportunity to filter out these friends’ requests.
I have many facebook friends who are just addicted to facebook apps and contribute largely to invitation spam. On the other hand I also have celebrity bloggers like Darren, Amit, Thilak in my friend list and I will definitely love to try applications they suggest.
(Source: Facebook Developers blog)