This is called Web 2.0 Submission or Social Media sites submission.
All in all, these are also the other SEO Linkbuilding Techniques:These strategies are known to be Intermediate SEO Linkbuilding strategies:1. Blog Commenting 2. Forum Posting 3. Web Directory Submission 4. Social Bookmarking 5. Web 2.0 Submissions
1. Article Submission 2. Press Release Submission 3. Micro Blogging 4. Shared Content Site Posting