Of what use is the sending bar?

[Wabbit]

When I send mail using 2001061608, I now get a small progress bar. 
What's the use of this bar.  All it shows is a barber-shop pole style 
image.  It doesn't show any progress, I can see.  Why is it there?

Just curious...

Wabbit

Anyone notice that if you add an address from the address book before 
adding an attachment, you aren't able to add the attachment?