GMAIL Does Not Recognise Dots(..)

Hi friends...
Its quite surprising and interesting.we have been using gmail since years.But you may not notice this feature.It doesn't "recognize dots in username."
At gmail log in page you can enter any number of dots in username.gmail ignores it as such.

For example if your usenrname is xyz@gmail.com then,if you enter

x.y.z@gmail.com
x.....y.z@gmail.com
xyz...@gmail.com

or any number of dots , with same password it log ins succesfully.Try it Once:)