OpenID is very useful in logging in to many sites. You only need to remember your OpenID and that's it.
I got a problem with one of my OpenIDs, the one from launchpad.net. It is not being accepted in UPITTC website. I wonder why...
Anyways, for those who want to place their comments here in my blog, you may use your OpenID to login. That will save a lot of time for you.
For more information on using OpenID, you may visit the the OpenID site. There's a lot of stuff you will discover with this thing.