There are many sites and technologies out there which search and aggregate news content and most do it pretty well.

Various news search engines have come and gone over the years, or adapted and presented the news in a variety of different ways, the most well known examples being Google news and Yahoo news. They both use a similar technique to sort out what news is newsworthy - the process by which news is pushed to the top of the agenda is based around proprietary algorithms that take into account factors such as recency and topicality (number of similar stories).

Sites such as Digg and Newsvine take this concept further.  They don't rely on search and feeds, but instead use the power of human referrals.  As readers express interest in an online news article, through a simple click ('digging' the article), it rises up the agenda and therefore in importance on the site. The user can be passive, sitting back and reading items pushed towards the top of the listings, or they have the power to influence what others read by effectively 'voting'.

Both models have many benefits, which is why they are successful.  But, such models struggle to identify the breaking news as it breaks. Both systems are held back because of the time it takes to gain the weight of numbers to push a story to the fore - be that the bespoke algorithm of the search site or number of votes on Digg type sites.

But recently, more and more prominence has been paid to the fact that true social networks, such as Twitter can break and develop news stories.  The plane ditching in the Hudson River, the Mumbai hotel attacks, and the China earthquake are both well known examples.  Here's Rory Cellan-Jones, the BBC's technology correspondent, explaining how Twitter broke the news to him

of the plane incident and the renewed concerns over the health of Steve Jobs of Apple.  In previous articles he has discussed Twitter's influence in both the the China earthquake and the Mumbai attacks. 

The problem as he explains in the Mumbai article is how do the audience know who to believe?  What's truthful, and what's not? Who is credible and who is not?  Who can we trust, and who should we ignore?