fathom - 3:22 am on Apr 13, 2012 (gmt 0)
Here is site history. Old domain 10 years had one seo work on it back in the day directories were the thing. Looking at his profile I can't find anything jump out. Old site as I said has a resource page with some links. None of them are in an anchor text, all good sites most of them old. When I say old over 8 years.
The only thing I can see were this site could trigger a email on the Google Webmaster Tools notice of detected unnatural links.
Forget looking for anything specific. Do broad strokes firsts.
What's going on in Analytics of the past year?
He has a page on his blog to be specific were he has in text "Advertisements Add your Link here" and some of the partners added from the resource page. He was trying to increase revenue anyway he could. This was added years ago like 5 or more so really nothing new. I guess the tweek has to pick up on terms within the site and if this has a links page could cause the email.
The problem with this style of research is... if what you see has nothing to do with anything Google found you'll start digging and finding what you want to see and not what actually occurred.
Again... you research MUST start with Analytics.
If anything occurred where Google took action you will LIKELY see a drop in traffic.
It may not be a massive overall drop it could be a topical drop if say unnatural anchor targeting occurred... this would produce a drop in specific phrases where an overall upward trend which could cover a specific decline.
This is where wmt Keywords can help drill down a traffic drop due to a unnatural targeting starting at the top of the word list and moving down.
Nothing else there took some time looking over the site. The blog is really a good one full of good information for the user, he hasn't lost positions so far. Nothing else there. Like I said in the other post he hasn't had any SEO work done on the site in years, no new links added in years on the links page. All of the outgoing links are quality sites. Got to be the Advertising and add links on the same page to cause this.
No anchor links as I said, no bad links, profile is fine nothing jumps out he has affilates but these are linked differently so they don't show up in profile.
Google (John Mu) has conceded that while a message was just sent the problem could have been there for a while... If a while it is possible the link credits can no longer be seen (to Google anyway).
I feel it is this one page with the text and partners that triggered the email all I can find.
I highly doubt that.
Google detecting that as "unnatural" isn't like looking for a needle in a haystack it would be more finding a specific needle in a stack of needles. The roar of natural linkage isn't all that different from the muffle cry of manipulation... I find it impossible to believe this would be the problem.
That said, if this is a case of selling links rel="nofollow" all of them fixes that issue... but I would move on.