Actually, WhatsApp service that targets Android and iOS. And they made adding contacts super easy. No ICQ number, no XMPP handle, no username. iMessage is Apple

Actually, WhatsApp service that targets Android and iOS. And they made adding contacts super easy. No ICQ number, no XMPP handle, no username. iMessage is Apple-only, Google Talk has a slightly different concept and more complicated. any messaging app included by default in Android will have users migrating in droves Yeah, that's why Google+ replaced Facebook and everyone is using Google Talk. Nearly every browser comes with Google as search engine or homepage and it didn't worked.