We do realize the potential SEO value of links in E-junkie Shops and Marketplace; unfortunately, black-hat SEO hackers also realized this and were abusing Shop/Marketplace listings as "link farms" to Google-bomb keywords linking to other sites, so we had to start adding the rel="nofollow" attribute to all links added in such listings.
Search engines, and Google in particular, frown upon black-hat SEO "tricks" such as Google-bombing and link-farming to boost page ranking in search results, and they are aggressive about blacklisting any sites they perceive to be link farms or otherwise involved in black-hat SEO activity, so we had to curtail that sort of activity on our site to prevent all E-junkie.com pages from vanishing off the face of Google and other search engines entirely.
