What is the main use of off-site optimization?

i use forum posting, social bookmarking, blog posting and commenting and article submission.

The main use of Off-Page Optimization is to generate Back links and promote your website on various High PR websites. Link Building is the main activity of Off-Page Optimization we can say. Article Submission, Web 2.0 Submission, Web Directory Submission, Social Bookmarking, Social Media Marketing, etc... are the main activities of Off-Page optimization. By doing the website promotion you can increase your website traffic.