You need a Spore-screenname.
When you start up Spore, look in the bottom left area. There you can click on the bar that says "Log on", or something with registering. Choose a Spore username/screenname, enter your e-mail (it won't be visible to other people) and choose a password.
Then you can log into that and share your creations.
We can add you as friends if you write your screenname here.