I am a firm believer in the value of reflective practice in learning. The opportunity to take time and think about individual learning at various stages increases increases personlization - and when you personalize learning you internalize and retain. Social media tools provide a variety of venues for this reflective practice. Blogs can be used as a personal journal to record stages of learning or projects. Wikis can also be used in this way, but would work better as a group opportunity to reflect on a project or assignment. Twitter can be used for more brief recording of thoughts and ideas. Facebook is great for group sharing and inclusion of a variety of media. Blogs and wikis are also very useful to encourage and enhance writing skills. A great resource for sharing and reflecting ideas is included with this link. Technology Tools for Reflection - Reflection for Learning
Whatever tool you use take time to reflect about your learning and it will be much more meaningful!
Just a few thoughts,