wow, almost missed this one -- just happened across Nat's post about Google Accounts launch on O'Reilly Radar, otherwise i probably wouldn't have discovered it until Google decided to tell people about it ;)
i guess this was/is a stealth launch, but i must say i'm continually amazed at how Google fails to announce/launch products with hardly any product marketing education or other evangelism & fanfare, and just expects people to just find it / start using it. (see my earlier post on "Google-vangelism... hello?"). at least now they appear to have a unified developer homepage for Google APIs & code at http://code.google.com/. still, i'm underwhelmed by the launch effort & awareness. seems odd that i continue to "stumble" upon major Google api announcements, rather than having them be frontpage news on GigaOm or TechCrunch or Cnet.
in any case this would appear to be a pretty significant development, and likely a great opportunity for developers to use Google as an auth /identity platform. i expect to see more of this type of offering coming from the GYM majors, as well as a few others. even if they don't get it right the first time, the trend toward hosted APIs from platform services should make the world a better place for all developers & users.
only question is, will Google (and Microsoft and Yahoo) make those platforms and APIs easy to use, easy to get data in/out of, what kind of infrastructure support & reliability they provide, as well as how they enable monetization. for both the major platforms & for new web services startups, these kinds of issues are exactly what i expect developers to be looking at as they choose API vendors, and exactly why i invested in a startup called Mashery.
look for more info about Mashery coming this week at Mashup Camp.