Google currently indexes apps.ycombinator.com and news.ycombinator.com and finds the same results. This is bad for SEO (not that it's really a problem for HN, but still not a best practice). As an example, I often get duplicate alerts from Google Alerts for terms that appear on Hacker News.So... apps should 301 redirect to news.
Incidentally (and this is not why i posted this) I created a small site called inboxSEO.com and we're experimenting with a content scraper that crawls a site and finds this problem, among others...