what is the basic difference between directory and blog submission ?[/QUOTE]
These both are the effective link building techniques used to build inbound links the your Website.
Directory Submission is to submit your Website into Directory Websites following their rules and guidelines. You need to submit your Website into appropriate category related to your niche and provide the required information.
Blog Submission is to create content related to your Keywords & Website and submitting those onto blog websites. Creating content for the people is better than creating content for search engines. Create unique and informative content, quantity and quality are the important aspects of creating content.