What are they?
Building Link Popularity Through Link Trading and Internet Directories
Unilateral or bilateral exchange of links with other websites. This builds page ranking, brings more traffic to your website and enhances website reputation.
1. Locate the right website
2. Send a good proposal
3. Set up proper linking text
4. Avoid gimmicks and bad link neighbourhoods
Internet Directories and Vertical Portals are websites that offer a large compilation of existing websites that are broken down into neatly organised categories and then listed in alphabetical order.
Also yahoo, MSN etc paid directories