——Instant Messaging & Web Conferencing——
Instant messaging (IM) is a type of online chat that offers text transmission over the Internet in real time. For Example, a chat box on a website for customer service.

More advanced instant messaging can add file transfer, clickable hyperlinks, Voice over IP, or video chat. Examples on those are Skype, Viber and Whatsapp.
Web conferencing services can integrate both video calling and instant messaging abilities.