A topic is considered "hot" on twitter if enough people use that word or phrase in their tweets. Now yesterday, one of the the hottest topic on Twitter was "Google Massacre".
Google Massacre, as you may have guessed, is just another PDF ebook on Google AdWords that promises "quick money."
The reason why this term managed to top the Twitter popularity chart is simple – someone created dozens of fake twitter accounts and published the same message on these accounts at the same time.
While this was quickly removed from Twitter Trends but all these "fake" profiles continue exist.