There's several tiers of indexing in Google Search (it's a pyramid, with Instant near the top when that existed), and lots of social stuff is refreshed very fre

There's several tiers of indexing in Google Search (it's a pyramid, with Instant near the top when that existed), and lots of social stuff is refreshed very frequently at the top of it. That is how recent Tweets show up in searches, as well. I'd be curious how often Googlebot hits HN.