Germany's online telephone book does reverse look-up. (People can opt out, but you know how it is..) Is that really so uncommon?

Checking some more countries.. the UK doesn't seem to have it, France does. Oh, there's a page for the US: http://www.whitepages.com/reverse_phone

Today reverse look-up is by design, it seems. The limitation before was probably printing paper and not just a design decision, I'd guess. I'm not sure whether I like the new situation, but then none of my friends actually has a landline.