So it seems.
It may just because of the sheer volume that reported problems are occuring now.
I think SEO targeting of Google is at a level never seen before. I think cracks may be starting to show if reports here of poorly relevant sERPS are any guide.
Why were these sites well positioned and now "shut down"? Maybe other sites have been optimized better since month? Maybe there are new sites and players? Maybe the reason for good positioning early was due to taking an advantage of a part of an algo that has now changed? There seems to be a perception amongst many here that if you have hold a top position for a while you somehow "own" it. That's a curious perception, and its pragmatically flawed. After the SEO community decided that Google was really the only cost effective search engine to target several months back, there is obviously going to be a lot more competition, a lot more spam (as guaranteeing top ranking long term by normal methods for highly commercial sites is illusory as I have argued previously), and a lot more sites, many vigourously SEO'd. Even 50 phds cant keep up with that, though when the pressure comes off in furture the relevancy for these types of queries might well improve, who knows? At the moment its a battleground out there for commercial sites. We know. We slipped in our commercial site this time, and several competitors have come in basically copying the key elements of it. We target other promotional avenues for this site, including Adwords.