It is a major problem with reddit, and could possible over time become a problem for news.yc, but it is not necessarily an insurmountable problem. For instance, if you really get a lot of submissions, you could pre-select probably-interesting posts with a text classifier and shunt them into a probably-interesting queue. (A text classifier could be something like the ones used in spam filters, or, if you want, you can throw the whole machine learning book at it and use Markov chains, neural networks, &c.)