Google is really trying to push Gmail – even if they don't know you or have your email address. According to Google, this feature lets you ''reach the people you know more easily'' and use the example of realizing you haven't exchanged email addresses with a contact.
But what it sounds more like is that anyone who happens across your G+ profile can now send you direct emails to your Gmail account whether they know you, hate you, want to creep on you, or just think you're purdy. As always seems to be the case with these ''improvements'' the default setting is to let anyone on Google+ email you, but fortunately you do have the option to change the settings yourself in a new settings category. Of course, if you don't know about the setting you could be getting all kinds of weird emails from strangers. At the very least people you don't know are limited to a one-off email unless you reply to them or add them to your circles.
The upshot is that people in your circles can get in touch with you even if you've never met which could be great for networking or job searching, but anyone on G+? That's a step too far in my opinion. It's kind of like making your Facebook profile completely open to the public – everyone wants at least a little privacy, surely. On the official Gmail Blog, Google state that ''your email is only shared with the people you want'' but what's the point of ''not sharing'' it with strangers if they don't need it to email you with anyway? Your email address will, however, remain hidden until an actual exchange has taken place between you.
The update will go live in the coming days and Google will at least inform you via email of the change and provide a link to the new setting. Will you be switching the default setting to protect your inbox from stranger's emails?