Sure, Google redesigns their navigation all the time, and it's not that newsworthy, but it appears the company has decreased the importance of Gmail, and is pushing Google+ even harder on their home page.
It's a big deal when Google adds more content to their homepage, and it looks like Google+ has been freed from the navigation bar and now floats on your homepage to give you a quick way to check notifications and share new content. This seems like it's to make it even more obvious to the user that the service is there.
I don't know about you, but I don't care about Google+, and Gmail is definitely the Google service that is most important to me. It seems strange that the company would demote it so far down the bar like this, when it's always been very close to the front. Only some users are seeing the changes, but it appears to be rolling out worldwide.
Update: It's official, the bar is rolling out over the "coming weeks" according to Google and is based on user feedback, apparently.