When I look at the URL to my profile I see https://meta.stackexchange.com/users/344066/jack-siro. I want to believe that
344066 is my userid or member number and
jack-siro is my username all automatically generated by the system. So why not have me sign in with my username like we do on all other sites like Facebook, Twitter, and so forth.
I would like to be using my username to login to SO. The system can make us have unique usernames to use to login with.