Over Thanksgiving weekend, HackerNews noticed they didn't rank for the search term HackerNews anymore.
It turned out, HackerNews blocked all GoogleBot IPs with the exception of one.
PG, owner of Hacker News said, "A couple weeks ago I banned all Google crawler IPs except one. Crawlers are disproportionately bad for HN's performance because HN is optimized to serve recent stuff, which is usually in memory."
Clearly that was a mistake and shortly after, Google delisted a ton of HackerNews.
It is a good thing Googlers hang out at HackerNews. In fact, it is one of the cool places for Googlers to talk geek at.
So over Thanksgiving, prominent Googlers including Matt Cutts and Pierre Far who work directly on Google search - worked to get the site back into Google's index.
In any event, HackerNews is now ranking for their name now in Google.
Forum discussion at HackerNews.