Jun 13, 2011 08:43 GMT  ·  By

The Facebook giant keeps on growing, it's getting very close to reaching the 700 million users mark, even though, officially, it's still at 500 million. But the growth rate is nowhere near what it was a couple of years ago and, even more worryingly for the site, it's starting to lose users in its earliest markets.

The latest data from Inside Facebook says that the social networking site reached 687 million users at the start of June.

It grew by 11.8 million in the last month, a healthy rise, but lower than in April when it got 13.9 million and significantly lower than the average monthly growth of 20 million users.

In most of the world, things are going as smooth as always, Facebook keeps on adding millions of new users each month in places like Indonesia, already its second biggest market, Mexico, Brazil, India and so on.

In the places where Facebook has taken off first though, the picture is not so great, it lost 6 million users in the US in the last month alone. It lost another 1.5 million in Canada and saw small losses in places like the United Kingdom, Norway and Russia.

Not that it's particularly surprising, there is always a stream of people leaving sites, even social ones, but most of the time, it's countered by a much bigger stream of people coming in.

When a market reaches saturation though, which is happening now in the countries where Facebook was incredibly popular early on, like the US, the UK and, yes, Canada, there are no more new users coming in, or at least, very few new users are joining.

So the ones that get bored or simply fail to log in for an entire month could easily overcome the number of people joining. That said, it's unlikely that this means that Facebook will start losing share in its most stable markets, the user number will probably stay constant, at least for the foreseeable future, even though there may be fluctuations from month to month.