Quote Originally Posted by Overtkill21 View Post
It has to do with shard distribution. When a shard fills you are placed in another, and if the player count is barely above the max player count for one shard then you'll be in a shard solo. I knew this time was coming, soon this won't be a problem as there will only be just enough players to fill one shard.
There are usually 3-4 shards that are running. You can verify this by using the social menu:

Friends in green are on the same shard, friends in red are on a different shard.

Pay attention to what names are in red go to a friend in red and see what names are still in red not including the previous green names as those would now be red since you are on a different shard than you started.

At any given time I can verify 3-4 different shards active. Except maybe first thing after a server reboot... I haven't bothered to look and see then.