Reverse speech is a common occurence in everyday life. In fact, many scientists believe that babies first learn to speak backwards (goo goo ga ga? anyone?).
It can be done as a way of reaching the mind subliminally, or it can come out of you without you noticing it.
People form interesting habits in speech, I for instance speak in Iambic Pentameter like 60% of the time. I had no idea till someone pointed it out to me and I freaked out.
I'm sure you live on the internet more than anyone else now...how on earth do you find all these sites? You must have so kind of super Google in your brain or something...