hottrout - 9:38 pm on Feb 22, 2012 (gmt 0)
I have to report the exact same problem with my site. At approx 18:00 GMT yesterday (21st Feb 2012) my root url / jumped from a daily average of 500 direct hits (no referrer) to 16,000 today (22nd). It does not crawl but the count is registered in GA. At the same time and as a result the bounce rate has jumped to 70% and time on site average has dropped. The hit seems to take 1s. It is coming from North America but spread over all regions.
It does not feel like any DOS I have seen but it is very weird. My forum (phpbb3) is also registering the stats as guest members which I find odd.
Does anyone have any clue as to what is happening?