Web directory and Bookmarking both are same?

Hello all,
Can anybody tell me web directory and bookmarking both are same? what is the difference?

directory submission and social bookmarking in SEO Most of the back links from Social Bookmarking is no-follow, While links from Directory are do-follow. Social bookmarking is a centralized online service which allows users to add, annotate, edit, and share bookmarks of web documents while Directory Submission is the activity of the Off Page Optimization