I heard on TWIT #382 the story of a "pump & dump" scheme : On November 26th, several news websites reported that Google was thinking of acquiring the startup "ICOA".
This wasn't news, but came from a public release by the firm PRWeb. The stock price of the small company went up just long enough for the authors of the scam to make a profit.
As a result of this, some news organisations have changed their verification methods, to vet even more carefully every story before runing it.
It is important to note that, by default, the Google news website can show press releases, it is a setting that you can change by going to news.google.com/news/settings :