Link seeding refers to the process of proactively surfing the Web planting links in websites that allow direct linkage back to your site, in the hope of attract PageRank, as well as traffic from those sites
Where can I seed links?
You can plant free links in web directory listings, forum posts, forum signatures, blog posts, blog comment author links, discussion boards, product testimonials, guestbooks, and wikis.
You can also submit your links to search engines purely, but they will only attract traffic. The links won't provide any PageRank because search engine result pages are dynamically generated, and Google doesn't allocate PageRank to dynamically generated webpages.
DEFINITION Link Spam is also known as Blog Spam and Comment Spam.
What is link spam?
Link spam is a much publicized form of spam that mainly targets blog commenting systems, but also forums, guestbooks, wikis (often called Wikispam) - in fact any website that allows people to freely post links.