What uses might you suggest that focus on 21st century skills and higher level thinking?

Any time you can get students to analyze, synthesize, or justify their thinking you are making them use higher levels of thinking.  Using the blog provides students with the opportunity to collaborate with each other and communicate their thinking to each other while using technology which is what 21^st century skills revolve around.    

I could really see myself using blogs in place of weekly journaling.  In the past, students would make a journal and then I would give them a weekly journal prompt.  Sometimes it would just be a silly one like “what geometrical shape best describes your personality and why?”.  Others take something we have learned in class and have them analyze it, for example “describe the method for solving systems of equations that you like best and state why you like it”.  The best part is that students would be able to see what others stated and comment on their posts.  It is like taking some of those great discussions that we have in the classroom and moving it to a level where students are not just communicating with me, but with EACH OTHER!