The work of link building is to determine the best combination of category and rank of link back website to achieve the link building campaign objectives.
In the process of shorting directories, forum, etc... the link builder needs to answer these questions such as:
How many of the back link can be achieve through the various link building technique?
On which categories should the link to be placed?
How frequent should the submission meta tag be change?
How much submission should be permit in each medium?
There are limitations in link building, so how much feasible these old technique are - Directory, Article, Blog, Forum, Comment, Bookmark, RSS, Classified, PR etc... Please do not consider social media as link building.
Your contribution as a comment and valuable suggestion will be highly appreciated.