It's an IM client that doesn't suck balls like Skype does. It doesn't do phone calls, but it's really low on CPU usage, the interface is really nice, and you can use little custom "stickers" as emotes and it's fun to use them to comedic effect, or commission ones specifically of your character, etc. The downside is that you need a phone number to sign up for it, because it was meant to be like a mobile chat client I guess? So when you sign up, anyone else who already has your phone number gets a little IM on Telegram that says "Sunes joined Telegram!" This means, if you sign up with a furry name, and someone like your cousin has your number and also has Telegram, they'll see you furry name and cat face. SO. If you decide to sign up, do it with like some rando name and discreet icon. Once you sign up, you can put your account to private and stuff so no one can go looking for you or w/e, and then you're totally golden to be as furry as you want. I think you can also sign up using a google voice number, but I'm not sure.

But yeah, it's got a phone app and a desktop client, and I like the desktop one a lot. So far my only complaint is the lack of /me functionality, but stickers make up for it in spades.