[Frondo]

Windows Phone goes one further: you can explicitly block any number.

Tap and hold on the number in your call history, and "Block caller" is right there!

[ableal]

> Tap and hold

Unfortunately, the "and hold" bit is rather hard to figure out. (And I started out knowing it could be done, but not how.)

There are some serious discoverability problems with the latest wave of pretty interfaces.