In an ideal world, some or all of the sites with large user databases (Yahoo!, AOL, Google, Amazon and so on) would act as OpenID providers, allowing their users to sign in to OpenID supporting sites around the Web. Until that happens, people who want to use OpenID need to sign up for Yet Another Account to do so.
This is a good boost for OpenID. Sam Sethi tried idproxy.net and hints that the big players like Yahoo, Google and MSN should support it. Brady Forrest notes the anti-phishing measure that Simon has implemented using MonsterID.
Simon has already paved the path for the big portal players. I think that it will also be easier for them to integrate the different companies that they take over, which has become a norm. I really hope that these big players start supporting OpenID, it will only make life easier for the user.