I thought of that, but the goal here is not to evolve into a site that's everything to everyone, like Reddit or Digg. We want to have the best collection of links for hackers. So we can't duck decisions like this.
We shouldn't expect never to have to ban a site if both (a) we want to make News.YC be about a specific topic, and (b) there are sites with a deliberate strategy of linkbaiting.
I don't think this would fracture the community much and it would probably do a tremendous thing to improve the signal to noise ratio for me personally. Not everyone has the same measure of what is 'signal' and what is 'noise', so I wouldn't want to impose my blacklist on them, and I'm not voting this stuff up anyway, so it's not like I'd be affecting other users by just not seeing some things. Even only being allowed three blacklisted links would be huge for me.
But honestly, not too passionate about this either way, just throwing in my two cents.
We shouldn't expect never to have to ban a site if both (a) we want to make News.YC be about a specific topic, and (b) there are sites with a deliberate strategy of linkbaiting.