For a few hours, I've been trying to register with Ubuntu One in the Software Center.
When I do come across a captcha that I can read, I'll input it into the registration form and immediately I'm told that I've inputted the wrong numbers for the captcha.
I was able to register through a windows machine, but entering that information into the Ubuntu One log in screen does not work.
Finally, I believe there is a problem with the captcha authentication system that you guys use. I know I've inputted the correct numbers at least 15 times in the three hours that I've been struggling with the registration process. I'm sure myself and others trying to register through that registration method would be extremely grateful.