how do people know to find the people that are tweeting the significant stuff?

so, for example....there was some guy at the political camp in norway, tweeting about getting shot at. (which is obviously awful, and i feel bad just mentioning that without it even being the real focus of my post)

i assume he was just joe bloggs....no one anyone would've been following previously...not like he's a news correspondant or famous or anything.

so how do his tweets get all the way to the guardian so quickly, if he's just johnny average.

how do the news know where to find the significant tweets?

do they all just get passed along?

i don't really now how twitter works, but i feel like i should now it makes up 90% of news reaction nowadays.

ta.