Now here is something which I personally think are rumours:
‘Helicopters pouring acid on people from the sky - #Iranelection’
(Persiankiwi)
And Winston asks back:
‘@persiankiwi r u sure? is it confirmed? how do you kno?’

Indeed!
A while ago, madyar tweeted that it was ‘boiling water’ …

So yes - one can sift the rumours from actual facts, even in tweets!