One of the common obstacles to using many Web 2.0 tools in elementary school and middle school classrooms is the registration requirement that those tools have. Fortunately, there are many good Web 2.0 tools that do not require registration. Nathan Hall has started to put together a Diigo list of Web 2.0 tools that do not require registration. When I saw the list yesterday it had 60 items. When I looked at the list this morning there were 101 items on the list. Take a look at Nathan’s list and I think you’ll find some new-to-you tools, I did.