The social network, which was unveiled in June this year, allows web users to share photos, chat to each other and leave messages and comments.
Furthermore, the social network benefits from Circles which lets users create lists of friends to share content with, as well as live video-chat for multiple users known as Hangouts, Huddle – a form of group instant messaging – and Sparks that lets users interact with others that have similar interests.
Initially, Google+ was released as an invite-only trial. However, during the 90 days the social network wa sin a "limited field trial", it attracted more than 20 million users, indicating it may well have a chance to rivalling the popularity of Facebook, which currently has more than 750 million active members worldwide.
"For the past 12 weeks we've been in field trial, and during that time we've listened and learned a great deal. We're nowhere near done, but with the improvements we've made so far we're ready to move from field trial to beta," said Vic Gundotra, Google's senior vice president of engineering, in a blog.
The search engine also unveiled a number of new features for the social network, the biggest of which sees the video-chat function Hangouts, being made available on mobile phones. Google said the feature is available now on devices running Google Android 2.3 and above, while support for Apple iOS devices is coming soon.
Meanwhile, the web-based version of Hangouts has been given a screen-sharing ability so you can share images and documents with the web users your chatting to, along with the ability to doodle on Sketchpad or create Google Docs at the same time as chatting.
There's also now a Hangouts on Air feature that allows Google+ users to start a Hangout which the can then record and broadcast. The search engine said initially the feature will be restricted to a limited number of broadcasters, the first of which will be Black Eyed Peas star Will.i.am. Finally the social network has also been given an integrated Google search box so users can search the web without leaving Google+.