What makes the declines more surprising is a good percentage of my traffic comes from links and typeins, which would not seem to be strongly related to the SEs.
I cant figure out what has caused this to happen but can only guess it's somehow related to changes Google may have made to their algorithm several months ago. Can anyone confirm that or know/guess about other possible reasons?
If it's direct nav traffic then it's a bit more difficult to understand a precipitous drop, unless you are being "given less traffic credit" for the traffic rated as suspect, doubtful, dubious, etc. Therefore the "actual numbers" are being discounted. One more version os smart pricing.
Also direct nav traffic, even if it were dubious, would only show as down if it really was. Log file analysis would show the actual traffic to the sites regardless of quality. (One potential cause of an actual reduction in dubious traffic would be large botnets being taken out - but the sort of scale of botnet reduction it would take to cause a precipitous drop would surely have made the news.)
After thinking about this I now believe it's strongly related to the IE browser or Google search using the suggested sites feature with their recent upgraded versions.
The suggested sites also appear much more advanced to me vs earlier versions. That would seem to detract from typeins since as you typein the url (or the keywords in the url's) you see various suggested sites (including a lot of authority sites) and may tend to click on one rather than proceed with the full typein.