On the 25th, 26th and 27th of this month I saw traffic to several sites (all on the same topic) triple. I jumped for joy as over the three days it seemed to be a stable rise. Then:
the 28th, 29th and 30th gave practically no traffic at all. From elation to depression in six days. I can't see any update, my rankings do not seem to have changed yet the traffic from Google is almost non-existent.
Like I said, my rankings are still there, even increased in some places. How can traffic levels drop so dramatically without loss of ranking?
It's possible you are not seeing what everyone else is seeing due to geolocation or simply that you are hitting a datacenter where your site still ranks while it doesn't at others.
I agree that this situation is true but I don't think it applies in this case. I have a UK hosted site that only targets UK visitors - I work using two different ISPs in my office and results are the same. Unless Google is somehow specifically targetting my house and my computer I don't see how datacenter differences could be affecting me. Won't most of the UK be seeing the same datacenter information I am?