Sure. I don't see why not. Heck, go invite everyone. We won't always be able to play together for a variety of reasons, so the more people you have in your metaphorical back pocket, the better. Don't go posting clan advertisements in #Destiny though. That is looked down upon by the people on these forums. Let me take care of that kind of stuff, but definitely feel free to invite your friends, followers and anyone else on you would like to potentially play with. It would be awesome if this group grew and became a place for people to meet up, organize Fireteams, and plan adventures.