Some are fairly safe bets, though - if a company is defunct, it's not coming back. Same goes if it's purchased. And funding events or major press mentions are probably noteworthy enough to include.
http://news.ycombinator.com/user?id=pq
user: pq
created: 2 hours ago
karma: -5
about: Not you-know-who; just want to see how many people confuse him for me, since his stuff seems to get a ton of upvotes, automatically.