walkman - 5:20 am on Sep 11, 2011 (gmt 0)
Bing does it too. I tested it by accidentally ruining the template of a very popular page (for Bing) within a day or two the visits to that page stopped. Fixed it and then got another visit (to test the waters ?) and then a day or two later they came back.
The problem is that my BR is much worst with Google, due to the crappier, third tier keywords they send. The direct visits have about 15% lower than Google. Last time I checked, Ask.com sent the best one and then AOL.
Can't speak for "users" but I rarely spend more then tens of seconds in any page.
If users were spending just 30 seconds on the site, I do say that it would have been disastrous for it. (I read it as 30-60 minutes)