Source: http://www.free-seo-news.com/newsletter698.htm#facts
Having the wrong kinds of backlinks pointing to your site can get you in trouble. These tips will help you decide which links you need help improve your rankings.
- Links that are easy to get do not help your site. For example, creating a free blog and linking to your site won’t have effects on your rankings.
- Automated backlink creation is discouraged. Links that are automatically generated are not good for your site. They should use the rel=nofollow attribute, or you can get rid of them if you have too many of them linking to your site.
- Links should come from reliable and relevant sources. Evaluate sites and check if they have interesting content that is relevant to yours.
- Links should come from high-quality pages. This does not necessarily mean a high PR page. A new, PR 0 page from a high-quality site is a good backlink source.