This I did not know about and I'm surprised they don't get penalised by Google in some way at the display of search results stage. I mean sure, I suppose one can do the -pinterest trick, but it's still a bit weird that Google thinks search results that are pretty much the same site but from different tlds are not spammy. Do you think they will change this to prevent Pinterest from essentially spamming some search queries by using the tld hack?