Also, many people don't get the meaning/pun in the name at all (which probably is one of the reasons for writing it wrong). Even to me, with a good English level, it wasn't immediate because "what's up" is a very idiomatic greeting and not one that non-natives (or at least, Spanish people) tend to use in a natural way. It took some time to click in my mind.
That said, Whatsapp absolutely dominates chat apps in Spain... so I guess these issues are not that important after all. Or at least, not if you are at the right place at the right time.