That means that You are now invited "To join [and to] create a public Google profile" for Google+ ...which is still in Beta. I think it's still called Google+ ...Notice how I avoid punctuation next to the plus sign, to avoid confusing things. ;)
If this were Microsoft, I suppose MS would have called it something like "My Bing+", because they like the M-word so much that they've probably copyrighted it.
+You - You MUST have a Google profile, revealing your birthday. +You - You MUST have a Gmail account. No thank you.
Does this mean that all those Google +1 buttons I installed are for naught, because I don't have a GOOGLE PROFILE? Does this mean that all those Google +1 buttons I installed are for naught, because I don't have a GMAIL ACCOUNT?
MY QUESTION - Can others use the buttons, even if I choose not to?
Personally, I have ZERO interest in being "social". I always falsify my birthday to the outside world, to help prevent identity theft. It seems that now, Google wants to put every single data point about you ONLINE - Name, address, previous address, phone number, occupation, etc. Why not birthplace, mother's maiden name, SS number as well? No need, others will gladly provide that information for a fee.
This required Google whoredom is becoming a bit much, IMHO. If you want the best rankings, and/or optimized AdSense income.