According to a forum, Joomla is like #57 for top linked to domains on the web. All links from joomla and subdomains, EXCEPT for forum.joomla.org are very trusted links.
http://forums.seochat.com/google-optimization-7/footer-link-will-it-cause-problem-275149.html
Diversifying your SEO is vital considering the possibility that your main site could be banned in major search engines like Google. An SEO Monopoly can help you form multiple sites in your niche that attract your potential customers.
