Some of them do. Some of them do not. But its a really big hit and miss on the Hacker News. Its really a lot more 'balanced' on Lobsters or Reddit for example ... but its probably a lot more people read/open Hacker News then some subreddit.

What is a real mystery for me is sometimes I add some stuff to HN and it gets 2-3 votes (and misses everything). Then someone else does the same and it gets the Hacker News Front Page and 10000 views - where is the login in that? :)

Regards.