You're conflating two things. Reddit doesn't often break news, Twitter does that more in real time with its immediacy and reach.
Just like Hacker News is/was to TechCrunch, Reddit generates a news cycle, as in right now across the world there are cadres of journalists and bloggers using Reddit to source and/or get ideas on what to write and feed into the long tail.
Any kind of community can become very addictive, especially to people that are going through a lonely period with a lot of free time.
I know of somebody that's deeply engrossed with Skyscraper City even though she isn't an architect, just because it has an encouraging community and she has a 4 hour commute and works in multiple cities (which makes it very hard to get into an offline community)
It kills me to see the reddit-hate here cloud obvious facts. There are a number of things that reddit has gotten good worldwide publicity for or has had a hand in shaping. That's not true for a large number of sites. In terms of what reddit is, it is important.
