There will be many different responses, combination, usage and purpose and that's what I'm interested to know.
For myself, I use Hangout, Facebook Messenger and Text Messaging. I haven't found use for any other platforms, simply because most of the people I associate with aren't on other platforms at this current time.
What about yourselves? Tell me what you're using and this may even lead people to discover other apps that they might not have been aware of.