OpenID
For those who don't know, OpenID is a protocol with a simple premise: "Register once, login anywhere". You're only required to sign up and type your password on one website, which is your identity provider, and then use a URL to login on any OpenID-supporting website without typing the password or even clicking any "Sign up" buttons.
If you have a LiveJournal account, you already have an OpenID account as well (and possibly don't even know it!), of the form your_name.livejournal.com. You can try it — type this string into the text field on the sidebar, press Enter, and agree to trust this site. Voila, you're logged in! You can now click the "Profile" link, customize your screen name (nickname; the internal name used by WordPress looks ugly compared to manual registration, but it's of no concern).
If you don't have an OpenID account, I strongly recommend getting one, it's just as simple as registration on a regular (non-OpenID) website. You choose a login and a password and get an OpenID identity. There are many providers out there, for example, MyOpenID (identity URLs of the form yourname.myopenid.com) and Videntity (yourname.videntity.org) to name just two.
In short, it's really nice technology, easy to use (even if my lousy description doesn't make it seem so), and most importantly, you have a choice, as opposed to relying on Microsoft to control your identity, which was the central premise of the miserable failure that was Microsoft Passport, now known as Windows Live ID and only used by Microsoft itself.
You use WordPress OpenID plugin or OpenID comment for WP plugin? And welcome to OpenID community.