Earlier today, Google announced a new Gmail and Google+ feature  for consumers that could lead to more unwanted emails from strangers. However, the feature will be turned off by default for Gmail business accounts. The split shows how Google remains relatively conservative with its paying Gmail customers, even as it speeds up integration among its free services.
What's the new feature?
Over the next few days, when Gmail users start typing in a contact name in the "To" field, they'll see a suggested list of people in their Google+ Circles below the regular list of contacts from their address book.
By default, this list will include any Google+ user in the sender's circles -- even Google+ users who haven't reciprocated. So, for instance, if you follow a bunch of bigshot tech CEOs and venture capitalists on Google+, you'll be able to email them from your Gmail account even if you've never met. Think of it sort of like the LinkedIn Premium feature that lets you send InMail to any other LinkedIn member. Only this is free.
This is a bigger deal than it might seem because Google+ has become tightly integrated with other Google services. Anyone who signs up for a new Gmail account or creates a Google Account just to comment on YouTube videos gets a Google+ profile as well. So you could start receiving strange emails from people who follow you on Google+ even if you're not actively using the service. (Fortunately, they can't see your actual email address unless you respond.)
Google+ account holders who don't want this extra email will be able to limit access (see screenshot below), or turn it off entirely. But by default, it's on so that anybody on Google+ can email you.
What's the deal for business Gmail users?
Now, the (slightly) better news. Users of business Gmail accounts won't see any of this integration unless their domain administrator has taken pains to turn it on.
First, business Gmail accounts do not have an associated Google+ account unless an administrator has connected the two services. So chances are, unless you're one of the rare businesses using Google+, random users won't be able to contact your work Gmail account this way. (However, if your organization is not on Gmail, and for some reason you used your work email address to sign up for Google+, you could suddenly start getting emails from strangers who follow you there.)
Second, even in organizations that use Google+, Gmail users won't see the dropdown menu of Google+ contacts unless their admin has specifically turned it on. They'll only see regular contacts from their address book. This would prevent -- say -- a rogue user from using a business account to send out spam or solicitations to a bunch of random Google+ users.
Overall, this change doesn't show a lot of concern for casual Gmail users who don't want the Google+ baggage to come along for the ride. If you sign up for LinkedIn, there's a plausible chance you want certain strangers -- recruiters, potential business contacts -- to find you and get in touch. That's probably not the case when you sign up for a free Gmail account.
It's this kind of move that continues to give Microsoft ample ammunition for its "Scroogled " campaign.