Use your Google account, for example your GMail address.
If you do not have a Google account then get one for free.
About Blendapps Chat
With Blendapps Chat you can chat in realtime from within Facebook or Ning networks using
top of the line chat solutions from Meebo or Userplane. Chat with your friends, exchange
images or videos, video chat using web cams - all without any extra registration for your
Facebook friends or Ning users. Of course Blendapps Chat is all free to use!