Dive Summary:

• Webmasters have reportedly received warnings of “unnatural links” on their on Google Webmaster consoles, indicating that bad links may be worth worrying about.
• There are numerous tools online for identifying and initiating removal campaigns for bad links, including SEOGadget, Remoove'em, Rmoove and LinkDelete.com.
• Bing has already introduced a means for sites to "disavow" bad links, and Google may launch something similar.

From the article:

Ethical link building for ecommerce sites requires hard work, creativity and a bit of good fortune. It’s tough to get quality backlinks to commercial sites, and many shops have wittingly or unwittingly (through contractors) engaged in spam or borderline spam activities to get them — including paid links, blog networks and comment spam. ...