This has been something that I've thought about quite a lot of late, and think is definitely going to be the case. My personal idea is that there will be a lot of people who would previously have read local newspapers but would rather read a social news site online.
The problem with current social news sites for these people is that they are too focused on particular subjects, for instance tech or business. So in between university and another proper startup I'm working on I built a site that lets each user view their own stream of stories agnostic of what the rest of the user base is doing - unless other user's stories or comments overlap with those of the first user. You can check it out at http://memescout.com!
Now the difficulty is getting people to use the site!