The great thing about sharing online is that you never know who is going to discover what you share. Something that you think has been said one hundred times over might be brand new to someone else. We all have something to share.
having students write a weekly reflective blog post. They don't have to write complex blog posts, just a short summary of their learning and observations that week will do. In this way students can learn from each other. Even if they don't pick up anything brand new from this process, they will at least be reminding each other of what they have learned that week.
One of the reasons I sometimes hear people give for not blogging, Tweeting, or otherwise participating in sharing their ideas online is, "I don't have anything to say." To that I often reply, "yes, you do."