chazeo - 8:32 pm on Feb 7, 2013 (gmt 0)
After a bunch of research, I found that Webmaster Tools > "links to your site" showed a domain.ru (a Russian language PR checking site, I believe) link. Upon further review, I saw that it showed that Google first discovered it on 1/2/2013! That is the EXACT day our organic traffic plummeted off the cliff!
Sure it's possibly a coincidence but, here's my questions:
1) Could this ONE link harm a PR5, 3-year old site with historically strong rankings?
2) Would I need to use the Google disavow tool? I have never used it before...