What is Canonical SSO provider?

SSO is short for Single Sign-On. It is a central identity service you can use to log into a large variety of other web sites and services without having to remember a different username and password for each one. For example, it provides authentication service for Launchpad (a project hosting and development site), Ubuntu One (a file hosting cloud similar to dropbox), askubuntu (a question-and-answer help site for Ubuntu), the Ubuntu forums, and even unrelated services such as disqus (lets users comment on blog articles).

How does SSO relate to the Ubuntu operating system? If you just want to install and use Ubuntu, you don't need a SSO account. But if you want to participate in Ubuntu development, you'll need access to Launchpad, which requires a SSO account. If you want to buy commercial software for Ubuntu through Software Center, you'll need a SSO account. If you want free or paid file hosting at Ubuntu One, that also requires a SSO account. And it's required for datacenter management services with Ubuntu Landscape, plus a number of other sites and services related to Ubuntu.