I learned (from Jorge Castro) that links on Ask Ubuntu are nofollow. Thus linking to some page (say, spam) in a post here doesn't increase that page's rank in search engines.
Is this the case for links in all user-contributed content? Or are links nofollow only for new users (or users with less than some amount of rep or time on the site)? Are links within the site (for example, to another post here) nofollow, or just those linking elsewhere?