In the next year, Google+ is going to be the second largest social site after Facebook in the US, as noted by a new study.

The unstoppable growth of Google+ is going to  eat a  large chunk of Facebook’s substantial base, according to the study released by YouGov, an international Internet-focused market research firm based in the U.K.

Head of YouGov investment products, Michael Nardis says Google+ got the fastest start among the social sites history in the recent years. To date, none of the current largest social sites today such as Facebook, Myspace, and Twitter have ever done that before.  Currently, the youngest social media have about 25 million users already, and there are around 16 million people who are thinking of joining the new social site by next year.  Google+ has become a threat to all the social sites.

On the newest report released by YouGov, Google+ is “well-positioned” to become the next biggest social site following only to Facebook in the social networking world in the U.S. within the next year.  Because of the momentum, Google+ has shown it should quickly pass other sites such as MySpace and microblogging site Twitter and LinkedIn.

Google+  first introduced by the end of June, and since then, it showed that it can be the rival of Facebook over the coming years as it manages to increase its users by as much as 25 million within a month of existence.   The new site manages to achieve this numbers, although Google is not advertising the social site.  People can only join Google+ by invitation from someone already using the site.

Now the YouGov study, which comes from 1,003 U.S. adults online between July 29 and Aug. 2, proves that Google+ is making progress. The study take note that even though Google+ is just new, around 13% of U.S. adult Internet users have their own Google+ account, with another 9% has intentions of signing up the by  next year.

Most of the users of Google+ are already active on the site. YouGov reported that 45% of Google+ users claim they participate in conversation once a day or even more.  Facebook has 62% of those surveyed.

Also, 46% of Google+ users claim that they are posting a message or links to the site no less than once a week.

However, not everyone have an account on Google+ is that occupied. According to YouGov, 31% of first adopters said they already leave the site or have not created any posted any message.

As Google+ grows, other social sites namely Facebook, Myspace and Twitter are going to have a tough time convincing their users to use their sites.