One thing that I have picked up upon in this thread is a recurring theme of "Old Results" showing.
I also check my rankings daily on a few keywords, and while it is difficult to remember exactly results from 6 months ago, it does have the look of deja vu.
There also seems to be two different issues repoted here:
1. Rankings the same, but traffic down...this I think should be a seperate issue.
2. Rankings greatly diminished....which I think is the issue at hand.
My D Day if you like was on the 5th of May. We had top ten rankings for virtually every keyword we target. Now while our site is 8 years old, we only started seriously building links within the last 3 months ( for the sake of argument I'm going to assume we have not got a penalty of some sort )
So on the 5th of May we dropped off the map literally. We didnt even rank for "my-domain" without the www & .com. We did however rank for www.mydomain.com.
After about 1 week we started to rank again for "mydomain".
We started to find minor pages in the site outranking highly optimised pages for a keyword.
We also started to find https pages that had somehow been crawled and were outranking the http equivalent ( the http pages were backlinked )
2 weeks on and we have some rankings in the .com version of G, not great, but better than it was. Now traditionally we see rankings improve in G.com, which then seem to get updated in G.co.uk ( the web ) then finally filter over to G.co.uk. This does not seem to be happening now.
For example I have tracked serps from G.com, making a note of who was above us and who below, for a given keyword. Then I have gone back to G.co.uk ( the web ) and the serps are accurate except for where our site should be ( we are pushed way lower, with a different url to the higher one in G.com )
The only difference for our site is that 95% of our link building has been done in the last 3 months, whereas our competitors have been doing it for a lot longer.
To me it looks like everything done in the last 3/6 months has been discounted, which would explain the above. I dont think I'm alone either as there have been similar comments on this thread.
Dont know if any of this helps, and I know its a bit of a ramble, but can anyone see a pattern here.