Its of my opinion this particular situation has really affected one of my sites to the point every url is banned from google. The same time these links appeared is the same time we lost all ranking for at least 10-15 solid keywords on first page of G.
They do not seem to hurt sites for Bing or Yahoo…
I have filed 8 reconsideration requests, and submitted several forums and have begged google to stop evaluating our link profile on these links.
I have 3 super affiliates who have told me once these links are removed – the site will reappear as it was before these links happened (they had same situation happen).
Problem is google will not reply and its been a while since i submitted another request.
These types of links can easily tip the scales and teeter tooter your site to the dark side.
Do whatever you can to get them removed – they destroy!