Queues Don't Fix Overload
As far as I know, queues are used for decoupling two systems so that you can scale individual components easier. In the example used in the article, adding more pipes out the wall.A queue has a perk of smoothing out the peaks which may give the illusion of fixing overload, but really you haven't added any capacity, only latency. Also latency is sometimes a reasonable thing to add if it allows higher server utilisation rates.