As a Google + and Gmail user, this doesn't sit too well with me. If you're on these platforms, soon you won't need someone's email address to send them an email, which means someone else won't need your email address to email you.

Google has just unveiled a new Gmail feature that will allow any Google + user to email any Gmail user, even if they don’t have their email address.  It means exactly what it sounds like- complete strangers could be filling your inbox.

The new feature will appear as the default status on all Gmail users’ accounts but rumor has it it'll be possible to opt out.

Google says the new feature will make it easier for people who use both services to communicate with their friends. "Have you ever started typing an email to someone only to realise halfway through the draft that you haven't actually exchanged email addresses?" the company asked in a blog post announcing the feature. "You're in luck, because now it's easier for people using Gmail and Google+ to connect over email."

Critics aren't crazy about this new feature and say it's invasive and should have been originally established as an opt-in feature.

So what do you do if you get an email from someone you don't know outside your Google+ circles? You can decide whether you want to receive future emails from the person:

  • To allow future messages, reply and add the person to your circles.
  • To block future messages, click the "report spam or abuse" link in the message.

If you ignore the email, the person won't be able to invite you to any new conversations, but they could reply to their original message.