Any chance this means Google is going to back-pedal on Google+ ?
I'd welcome Google splitting it's products such that you can subscribe to YouTube without also being signed up to Google+ and GMail and Maps and the kitchen sink. Or vice versa.
Why?
Remember, you're the product in all those services, and by forcing G+ on you, Google's enhancing the product for sale.
About the only thing is that they can take back the whole "Steve Jobs said G+ was a joke" thing, but really, G+ is a great way to get back at Facebook. Because well, Facebook aims to be a closed community - Facebook's tracking is limited to sites that have Like buttons.
Google's ability to sell ads (Facebook can only sell ads within its network - it doesn't sell ads outside of Facebook, yet) means it reaches practically the entire Internet (Google, and Google-owned ad networks are around what, 98% of desktop browsers, and practically all mobile browsers), meaning it's out-Facebooking Facebook in its ability to gather user information (i.e., non-voluntarily-provided information), thus offering advertisers a far better product.
Sure its last results are down, but they're still massively profitable, and within a short period of time (cost-per-click is down, which means the last 2% are dying) Google would really get at everyone.
Hell, Android was released just so Google wouldn't be locked out of iOS ad sales.
Face it - Google's addicted to ad money, and Google knows it - it's their massively primary revenue stream, the alternatives are a joke (iAds - you get LESS information about users from them than Google, they cost mode, and are limited to iOS), so Google's really the big guy. Google's trying to save Google Glass before the internet brands it as an always-present surveillance camera worn by people with more money than sense (i.e., Glassholes). Because otherwise it'll kill it as a data gathering option Google has to sell more ad data.
Hell, think GMail's picture-proxy is for your safety by "not reveailing your IP address"? Why bother, when the proxy will happily load you tagged images confirming your e-mail address and that you read it. Perhaps think what Google has next in store - i.e., that Promotions tab might be the phase.