"YES!" was my out-loud reaction to Google's latest update to its multiple account sign-in feature. Currently an opt-in tool, new Account Chooser simplifies the login process, greatly reducing the number of times you have to re-enter your usernames and passwords throughout the day.
First spotted by The Next Web, the Account Chooser applies to both personal accounts and Google Apps, and works with most popular Google services, like YouTube, Gmail, and Google Plus.
With the Account Chooser enabled, the sign in screen will display all of your Google accounts, accompanied by their respective profile photos. Meaning, you'll no longer need to enter your e-mail address each time you want to sign into another account. Once you sign into all your accounts, Google will keep you signed in until you've manually signed out or are inactive for a significant period of time.
Although this update doesn't bring a significant change to multiple sign-ins overall, the minor tweak does relieve some of the annoyances associated with managing a handful of Google accounts.
Google hasn't yet implemented this feature for all users, but you can opt-in to it on this support page.
According to Google, the following services are compatible with multiple account sign-in: Alerts, Calendar, Code, Docs (Google Apps accounts only), Finance, Gmail, Google+, Google Moderator, Groups, iGoogle, Maps, News, Profiles, Reader, Sites, Voice, Web Search, and YouTube.