In mid March one of our sites <snip> took a nose dive in the Google serps and moved from the top of page 1 to page 6. About a month later it took another hot and got swiped all the way down to page 25.
In the intervening months I have cleaned up the site with regards to duplicate content, checked canonical tags, seo's the blog, rewrote any problem meta descriptions and Title tags and pretty much gave the whole site the once over.
6 Months on and as of 2 weeks ago we have now moved up to page 8 but no further.
Now for some more detail:
The <snip> site is one of 4 sites we run which are all build around exactly the same structure. When we do changes to one site we replicate it on the others. The other 3 sites took a little hit on traffic for a while but are all still showing on page 1 for their respective keywords.
The only thing that is different between the sites is the in-bound links. Weirdly in January we discovered via GWT that a couple of e-commerce sites from Asia had over 4000 backlinks to <snip> anb contacted them asking that they be removed. The problem was that they had put a link in the footer of their e-commerce website and since the two sites between them had over 4000 products this became the number of backlinks.
Now I have spent some time on the Google webmaster forum and asked whether anyone thought that these backlinks could be the cause of the serp drop and everyone dismissed it because Negative SEO is not possible. However this morning I read a comment on a blog on seomoz.org (see quote below) which seems to show that it is possible and may be the cause of our problem.
We recently got caught out on a site (one of our own) by submitting to a directory with very targeted keyword anchor text. The directory in question added our link to its latest links section which was in a side column thus displayed on every page of said directory, Google happened to crawl several pages of that directory over a two-four day period so the number of links with that exact anchor text went through the roof, result being a 8 page drop overnight
As things stand at the moment both the sites have removed the offending links, the first in April and the second only a week or so ago but after some overt threatening.
The whole saga has been rather taxing and hugely time consuming and although I have learnt a hell of a lot over the last 6 months I really do feel that Google have messed up with their new algorithms by opening the door to the dodgy quarter of the SEO community.
Anyway, I figured I share this with everyone in the hope that more people become aware of the problem.