In my classroom, I have an LCD device but I cannot send out websites to the students. (Emailing website URLs is a chore.) They have to copy theURL and then enter them. Whenever I give them a long URL they often make mistakes in copying it. The solution is the tinyurl site which takes a long URL and converts it a very short URL. For example, http://www.authenticeducation.org/bigideas/article.lasso?artId=63&-session=Auth:8D95D4D40533c2028AMsFEF5FFBB
Converting to a tiny URL works great for twitter or written material.
Try it and you be amazed at how it makes it easier for your students!