No kidding. Their privacy policy:
"When you give WhoApp permission to do so, WhoApp accesses your mobile phone’s address book and collects the names, phone numbers, addresses and certain other information about your contacts ("Contact Information"). WhoApp incorporates Contact Information into a database that it maintains of all its users’ contacts (“Contacts Database “). When your Contact Information is incorporated into the Contacts Database, it is no longer linked or linkable back to you. The Contacts Database is used by WhoApp and by apps that are offered by the company that offers WhoApp (or its affiliates) to fulfill customers’ requests for service and to improve each app’s services for its customers. PLEASE BE AWARE THAT IF YOUR PHONE’S ADDRESS BOOK CONTAINS AN ENTRY FOR YOU, THAT INFORMATION WILL BE DOWNLOADED TO THE CONTACTS DATABASE JUST LIKE ANY OTHER CONTACT INFORMATION."
No thanks - I don't want my friends/family (with address and pictures?) to be entered in here, and I hope they wouldn't either.
Edit: Is this even legal? Sharing personal information of others w/o consent? This is really scary/sketchy stuff. If each phone has an average of say, 50 contacts, and they get 100,000 users...