Destiny online raids are only playable with friends, no strangers allowed
It turns out that the raid missions in Destiny won’t be playable with strangers. You can tackle these raids in parties of up to six friends online but only people on your friends list.
Bungie says some of these raids will be so massive it could take a couple of hours, thus being more suited for play with friends rather than strangers:
The activity is going to take you and your group of five buddies into a place that you’ve never been. A place that you will return to frequently. And [it will] demand of you things you’ve never even really been asked to do in a shooter before.
Sounds interesting to me. I can’t blame them for going this route as cooperative modes like this in shooters typically don’t fare well with strangers, especially as missions take longer and people drop out.