I think the bigger difference in MM through the game (in this case you do it on forums and the companion app) in an mmo and MM through a built in system is that when you get a raid group together in an mmo you know they can complete the content because you have spent all that damn time attuning for it and everyone needs to be on the same level. A good example I would say goes similar to this: Early on you start running dungeons (Strikes in destiny) to practice mechanics figure out your class etc. After a while you will start meeting some people in the dungeons that are playing very well (preforming their role properly) most likely a good idea is to friend invite that person. By the time you have hit level cap (lets not say level cap for Destiny and just say this point you'd be about lvl 20) you have met a few of these people and have been grouping and talking with them maybe one or two have a guild maybe not but either you would join theirs if it was ready for endgame all join another or start one of your own either way this is just a fireteam in Destiny so it's much easier. Anyways NOW you are ready to start attuning to the raid (20-25 strikes in Destiny) which you would most likely run together and by the time you are done doing this the 6 of you have put in some good hours playing with each other and if you are good have learned each others play habits rotations synergies etc. This is where you would start raiding. So the difference for me between MM and grouping up/playing with people in game of my own accord? I have played with these guys for hours and know what build they are running what gear they use what skill rotations they use and that allows me to know what skills of mine to use when and how they will react to a situation like a fight gone haywire which will be what makes us succeed in a raid. The raid designers aren't asking you to compare just inviting a random in the tower to a MM system those 2 scenarios pretty much are the same and both are bad options. The point is to be inviting people in strikes together finding people you enjoy playing with long before you are able to raid, IF your aspiration is raid, by the time you get there you will have been playing with your raid fireteam already. P.S. none of this post mentions you needing to have a friends list prior to the game this is assuming your friends list is empty before you start playing.