Basically, just copy+paste the style and functionality from WoW. You currently have Unranked PvP MM (matchmaking) and Heroic Vanguard MM, just like how WoW has Normal/Heroic Dungeon MM and Unranked PvP MM. However, WoW added an in-game feature with the last couple of tiers of Mists (the expansion before Warlords) where people can list groups for activities and people can apply to join them. This is the primary way that people find groups or fill up empty slots for Mythic Dungeons (Nightfall in Destiny) and Normal/Heroic (and sometimes Mythic) Raiding. Destiny needs something similar. Having to use an external source or hope "friends" are online when you want to do your Nightfall or get in some raiding is really tedious, time-consuming and not easy in many cases. It'd be really nice if you could just log onto into Destiny, and if you felt like doing your Nightfall or downing a couple of raid bosses just bring up an in-game menu and browse for people or groups looking to do the same thing.