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In case you had any doubts about it, OpenID has definitely proving to be the de facto standard for web identity. Many big names, including Google (through their Blogger service) and Yahoo announced their support for the standard, and now five big companies join OpenID Foundation's corporate board: Google, IBM, Microsoft, Verisign and Yahoo.
The foundation is not open only for huge corporations; basically, anyone can join - for a small fee. Students will have to pay their membership $50 per year, individuals will have to cough up $100, while companies have to pay various fees depending on their size.