The URLs of these online applications:

www.youtube.com
www.facebook.com
http://www.skype.com/intl/en/home
http://www.msn.com/?st=1
www.google.com
http://sg.yahoo.com/?p=us
www.blogger.com
www.twitter.com
www.gmail.com

Among these online apps, my favorite app would be Facebook because I am very familiar with it and it also allows me to communicate with my friends and see what they're up to by checking their profiles. I can also update my status so that my friends know what I'm doing as well.