I love Telegram, it's a lovely Android and Windows app. It looks a lot like Whatsapp but I feel like it's a lot better. I chat on it every day almost all day with both people I know and people I don't know. The group creation and management features are just excellent.
If you're using it and would like to be contacted just say so (through public or private message). If you don't use it, you may try it and say what you think about it, or say why you won't use it. And if you used it and don't anymore, please share your experiences. I myself have been having a wonderful time with it. I'll also post a poll just to see how many use it.
I've never heard of it but will definitely be trying it out. Aptly named as well!