I love viber, everyone i know uses it and its free instant messaging but here are a few tiny annoying problems, all about groups.
1. Anyone can add you to a viber group without permission, even if all they have is your number and you didnt accept no friend request.
2. You cant create a group with 2 people, it will send you to that persons viber profile to private message them, what if you want a secret group, or if you want to start it of with you 2 and add people later too.
3. You cant create a group with people who are in another group (lemme explain)
If you try to invite Jake and Josh for example, buth both of them are in another group with you, you cant.
AAAAAAAAAAAAAAAAAAAAND thats it, just some random shit that popped in my head but yeah viber groups have their problems although they are certianly a cool way to communicate.