On my realm, kul'tiras, there is a group of obvious hackers who control several characters, around 30 or so and create "shapes" with them to spell out websites that I assume are for gold selling. They are all controlled at once and move quickly and float through the air to make the shapes and words.
"Body spam", put into an in-game ticket, usually gets this sort of thing looked into fairly quickly. :)
^^ This.
While you are welcome to report these, they are usually handled routinely by our crack spam eating gremlins - it can take them a little while to get around to all of them :)