Elsmarc - 5:36 pm on Aug 27, 2012 (gmt 0)
@netmeg - I agree. An advertiser on my main site put me in contact with his "professional" SEO guy. One of the things he immediately focused in on was how many external links are pointing to my main site which did a dive on 25-28 July 2012. He was very concerned. In an email a few days later he essentially said he was checking backlinks many of his other customers had from scraper sites and such and he concluded that it probably wasn't an issue. He told me he had never worked with a site the size of mine, much less one that had been on the internet as long as mine so he didn't well understand the significance.
I will say one thing, it pretty well demolished my opinion of "professional" SEO people (not that I had a good opinion of them prior to this event) even though my advertising client raves about how good he is. He was even unaware of URL parameter settings in WMT and their importance in forums (not to mention other dynamic sites). I will say *I* was pretty much unaware of WMT until Google trampled my main site. So - I did what I had to, which was to jump back into SEO again part of which was learning every aspect of Google's WMT and I also signed up with Bing's version of WMT and have dived into that.
@atlrus - I see you've been here since 2004, as have I, so I give you your due. But I think you're fooling yourself. If a web site becomes popular at all there are going to be thousands of scraper sites linking to it. I haven't done any SEO in years. The "drop off the cliff" my main site took kicked me into action to look at the "current state of the art". I now believe that the more "spammy" links to a site there are (not counting purposeful SEO spamming blogs and such), the more popular / well known it is. I have a hard time believing Google isn't aware of that aspect. We *all* know we can't "clear" those spammy links from other sites.
That said, there is a difference between spam from scrapers vs. spam posts on web blogs and such that many SEO people used to "help" their clients. I loved this one (I apologise if I'm breaking a link rule here): [talkingpointsmemo.com...]
As an aside, my main site took a 3 week dive (and I do mean DIVE). It's now slowly clawing it's way back up despite a few hundred thousand "spammy" links to it from scraper sites. I don't expect it to reach the height of it's past peak of January 2011, but one never knows.