What constitutes 'chat' data usage?

[fdxorf]

I am new to the smart phone world, so please excuse if this is a stupid question.  I was looking at my data usage and noticed that 40% of my usage is for "chat".  What type of chat uses data?

Thanks

[Weth · Accepted solution]

Any service that is exchanging messages, videos, photos between people that isn't regular old text messaging.