I did wonder that. Personally, I put social events in my calendar but don't specifically invite the other people to it. I'm still validating the concept, but am initially leaning towards this being more of an integration with calendar services, particularly facebook where people probably do have common invites

I've only used FB events among friends for big events (Lets all go to Vegas!) and even then most of the coordination happens in a chat group.

> Do people send calendar invites when hanging out with friends?

I've literally never had that happen, personally. That doesn't mean it doesn't happen, though.