&gt;If 10000 Twitter users with 1000 followers each send a tweet, that&#x27;s 10000000 messages hitting queues.<p>if your system design is actually done that way, i.e. that that amount of actual msgs, in one shape or another, hitting  actual queues... well, you would definitely inflicted &quot;scale&quot; onto your system. It is like for any powerful data  system there is always possible to make a cartesian query that will kill it :)