There are several webmasters complaining in Google Webmaster Help and WebmasterWorld that Google has stopped crawling their site's as of yesterday morning.
Some say the crawling has not stopped completely, but rather dipped to a tiny fraction of the crawl rate they normally see.
Even senior member, Walkman, agreed and said:
I got 50 googlebot visits, down from over 1000 normally
There was some speculation that this was only impacting European web sites, but it seems to be larger.
Another senior member said:
Same here, daily average for the last 7 days was 20,000 gbot hits. Yesterday was 150 total gbot hits. Site is a US based site so I don't think this is a European only event.
Is this related to the Google Caffeine launch? I highly doubt it, being that Google Caffeine has been rolling out slowly and slowly over time, so I doubt it is specific to that.
Maybe it has to do with some sort of malware misclassification issue where Google will stop crawling sites until they are de flagged? Maybe it is something completely different. I am not sure.
Forum discussion at Google Webmaster Help and WebmasterWorld.