Don't know, but if you provide quality content it shouldn't affect you at all. I found out that people who I don't know "make" SEO for my site just because they link to various internal pages from forums, from their own sites, etc, etc. Based on latest G Sitemaps data I have 4430 external links pointing to my primary site. 1987 are pointing to the homepage; they're links managed by myself mostly. The rest is located on my blogs and on forums which I don't control anyhow. I count on that about 1500 links are somewhere where I haven't been ever.
Those general suggestions made by Google really work...
