They're rumors. By definition they're un-fact checkable.
Not really. Once a tech journalist has been around long enough, they probably know a few different sources from various companies who might be able to give them some further information about the rumor. A lot of sites probably ran it by someone who'd be in a position to know something about the rumors, and most of them probably got a response to the tune of "Sorry, doesn't match up with anything that I know."
However, once someone decides to post it, then all bets are off as everyone wants some of the traffic for themselves. Some sites might even post it along with some additional bits saying that they can't verify it or that their sources haven't been able to confirm the rumor.
All that aside, I'm a little disappointed as some of the rumored additions sounded cool. I don't know exactly what Google is working on, but they should definitely consider some of the rumored features for actual development.