A premise: For whatever reason, people tend to view Google as less of a brand and more of a utility.
Suggested reasons: Google is utilitarian. It's underbranded to the extreme, and even its logo is generic. Before anyone had Google accounts or Gmail, we were already using "google" as a verb. The lack of flash, the absolute dearth of iconography...the lame font and funny multi-colored name, these things are disarming almost to the point of making you forget that Google wants each and every bit of your personal information even more (perhaps) than Facebook does.
Facebook, on the other hand, is nothing if not a brand. Rightly or wrongly, we think we get what Mark Zuckerberg is all about, and that necessarily defines our understanding of his company's ethics, ambition, and culture.
When I'm using Google+, I don't feel like I'm in some proprietary fishbowl circa 1990s AOL. Google looks and acts like a utility, and we've come to think of access to what Google does best (search) as precisely that. Facebook is a fishbowl by design, and Zuckerberg's quest to keep you in/on Facebook for all your webly needs shows that he's bound and determined to validate and more effectively monetize Steve Case's old vision. But while Plus is built with the relationships working adults have in mind, Facebook was built as a college network. It has adapted over the years to fit the needs of older people, but in lots of ways, it still feels like your last visit to the pediatrician. Early adopters are hitting 30 and needing a social network that's intuitive and easily customizable, something more akin to real-world connections than "friending" and more useful and dynamic than boring old LinkedIn.
Last week we learned that Google will retire the Blogger and Picasa brands as they begin to roll those services into Plus. Is everyone starting to understand that Google+ is Google, and Google is Google+? Blogger.com is the epitome if Web 2.0 branding, and if you're not already using Picasa, it just feels like another thing. So Google is rolling these brands into itself, making them more useful and more generic than they've ever been. The lighter the brand recognition, the more likely we are to trust you with our data. Silly, isn't it, given Google's size, influence, and sometimes-faltering commitment to publicly stated values? Sure is. But it's also true.
Don't think so? Check out Delloitte's recent study proving that we already hate branded apps. While Facebook is busy becoming the largest branded app in history, Google is de-branding everything but YouTube (which also doesn't feel like a brand). Interesting, isn't it?