I run a medium size site that does about 1.5 million unique visitors a month. This year, on the evening of 12th Feb, our google traffic suddenly plunged by more than 60% or so. As per WMT, our impressions were down from about 1.3 million daily impressions to about 200k. The drop in traffic was less due to our brand queries.
And the plunge brought in the usual panic, making us think, what did we do wrong? Nothing was to be found.
Then about 8 days later, on the evening of 20th Feb, everything came back to normal. On its own. We made a minor tweak on the site, but I doubt such a tweak would cause such a quick reversal in traffic drop.
Life went on smoothly with the usual ups and downs in traffic(less than 5 per cent variation from our expected levels) until the evening of 5th June. At about the same time, our Google traffic plunged, exactly in the same way. Our Analytics accounts shows almost similar levels of hourly traffic between the Feb days when the traffic plunged and the currently depressed levels.
I'm not sure if our site is a 'brand', but there are more than 100k queries on our site's name or some variation of it on Google every month. We never had any major Panda or Penguin problems in the past and our site is super clean with decent backlinks.
I'm at complete loss to understand why we would have such a dramatic plunge in Google traffic, especially on dates which don't overlap with the dates of any known algorithmic updates.
My own conjecture based on the previous plunge and recovery is that there was a bug in the update that was rolled out on 12th Feb that got fixed on the 20th Feb, causing our traffic to revert to normal levels. And possibly the bug got reintroduced into the newer version of some update that was run on 5th June. The bug theory is also corroborated by a few movie blogs (and possibly other sites too) that got hit on around Valentines' day and their traffic magically reappeared after Matt Cutts' intervention ten days later. Another thread on this forum discussed this issue in detail. Here's a detailed analysis of this issue:
We are down significantly in traffic and revenue, but we will survive based on the direct, branded and bing traffic.
Any theories, suggestions, ideas on what we can do? Anyone else experiencing similar declines/recoveries.