In addition to this, there are differing scales at work. In real life, by your analogy, you might find a cinder block with a "throw me" note. With the internet,

In addition to this, there are differing scales at work. In real life, by your analogy, you might find a cinder block with a "throw me" note. With the internet, you might find a button that says "throw 1.4M cinder blocks." One maniac can cause much more trouble that way.