Communication is at the heart of community, both in practice and etymologically (meaning, they share the same root word, from the Latin 
communis, which I believe means 
common, or at least that's what I gather from my dictionary).
But, even a trivial amount of communication can lead to a community feeling, and thus I link for you this 
review of the game Journey at No High Scores.
There is also a button for speaking. Or singing. Or laughing. Or 
screaming. It’s your choice. The reason it’s there is because 
eventually, you will come across another pilgrim that will accompany 
you. It’s another player, although you don’t know who they really are. 
And you can’t speak to them except through this one button and what you 
do in the game. 
On my journey, I went through an amazing range of emotions, many tied
 to my companion. When he (or she) would be away, I would feel sad and 
look for them, pressing the button to see if they’d respond. When they 
did, it was a huge relief. We worked on  some of the game’s cryptic, 
simple puzzles together. We celebrated when we made it through an area. 
We laughed as we slid through the desert through crumbling gates left 
behind by unknown builders. We hid together from a giant dragon made of 
cloth. 
But his scarf was longer than mine, and I wasn’t quite sure why. I 
wanted mine to be like his. When we were close, we replenished each 
other’s energy. I can’t  help but think that maybe the other felt like 
they were taking care of me, sharing his wealth, knowledge, experience, 
and energy. 
Eventually, at the very end, I lost my companion during a dizzyingly 
ecstatic sequence that’s  best left for you to discover. Walking into 
the final section of the game, I was alone. I felt guilty about going on
 without my companion. Was I so caught up in my ecstasy that I neglected
 the person who walked with me all of this time? I stood on a cliff, 
pressing that button to see if they would answer back. They didn’t. I 
moved on.
I believe the button-press just makes your avatar "sing" a note, but I haven't played the game yet. You can probably find it in the 
videos at the Journey site.