OpenID - I just got one and most probably, you did too!
Today, Yahoo announced that they will support OpenID and that users will be able to use their Yahoo IDs to access other Open ID enabled sites. Here is the InfoWorld article with details on the topic.

I believe that OpenID has a real opportunity to reduce the number of ID / password each of have created on the web. However, it is a very tough problem to solve - remember Microsoft Passport?