We have all heard of Facebook and Myspace, and undoubtedly most of us have heard of a few other Social Networking sites, but I bet that most of us hadn't heard of at least a few of the sites on this list. These are the 10 largest Social Networking Sites in the World by number of registered users, many of which are hardly used by Americans or Europeans. Please note immediately that this is not the 10 largest sites by number of unique monthly visitors, many of these registered users may seldom use the site. This list may however help affiliate marketers and other online marketers, who had previously focused on Myspace, Facebook and Twitter for traffic. Where is Twitter? Its about 10 million registered users away from a place on this list; although I am sure that it will get there sometime.

1. www.Facebook.com (300m Users)

The world's largest social networking, unsurprisingly, is Facebook with an astonishing 300 million registered users. Facebook is a general purpose social networking site and is open to anybody aged 13 or over. I am assuming that nobody need an introduction to the second largest website on the Internet?

2. www.Myspace.com (264m Users)

In second place, and again unsurprisingly, is Myspace.com with 264 million registered members. Myspace, like Facebook, is a general purpose social networking site and is open to anybody aged 13 or over. Again, no introduction needed!

3. Windows Live Spaces (120m Users)

The third largest social networking site is Windows Live Spaces, which is effectively a Blogging platform. Windows Live Spaces was initially known as MSN Spaces upon launch in 2004 and was receiving around 27 million unique visitors per month in mid 2007. Windows Live Spaces works around a blogging them, whilst also enabling the incorporation of many Myspace and Facebook-like features. These include photo albums, lists, and profiles.

4. www.Haboo.com (118m Users)

Haboo is a social networking site aimed specifically at teenagers, and was first established way back in 2000. It now comprises of 31 separate communities known as 'Haboo Hotels' each of which offer user profiles and large open chat rooms. As of the middle of 2008 some 118m avatars had been registered and the site receives around 8 million unique visitors each month, its recent growth has been rapid with as many as 75000 new avatars being added daily. Each of the 31 hotels are based in a different country, with the first in London, before expansion into Switzerland, Finland, China and 27 other countries.

5. www.Friendster.com (90m Users)

Friendster is the 5th largest on the list with 90 million registered users, but is no longer popular in the Western World. It has however gained significant popularity in Southeast Asia, and it often remains in the top 100 most visited websites in the World with 61 million unique visitors a month and 19 billion page views per month according to Alexa. Australian based Friendster now relies almost completely on Asian customers, with 90% of its traffic coming from the continent. As of May 7th 2009 the top 10 countries accessing Friendster were the Phillipines, Indonesia, Malaysia, South Korea, United States, Singapore, China, Japan, Saudi Arabia, and India. Friendster was first launched in 2003 in California, way before the creation or launch of Facebook and Myspace, and the site found immediate success in the United States. The site encountered problems when Myspace (and then Facebook) stole most of its western users, but a release of 9 additional languages in 2007 has assured rapid growth in the East.

6. www.hi5.com (80m Users)

Hi5 was founded in 2003 by Indian entrepreneur Ramu Yalamanchi and is believed to have around 80 million registered users. Hi5 follows the generic social networking route of completing a profile, uploading pictures, and posting comments. The site also allows the user to create personal photo albums and set up custom music players. According to some sources, hi5 was the third most visited social networking site in terms of unique monthly visitors.The site was created and is headquartered in the USA but has become popular in other countries, particularly Latin America, India, Portugal, Central America, Mongolia, Thailand, Jamaica, and Romania. It has never been popular in the United States or most of Europe.

7. www.Tagged.com (70m Users)

At 6 on the list is the general social networking site Tagged,com, which was founded in 2004 and is headquartered in San Francisco. Like Facebook, the site initially targeted high school students but is now open to anybody aged 13 or over. The site allows the user to build customizable profiles, send messages, and leave comments - features found on either Facebook or Myspace. It also uses YouTube videos and widgets, The site began to break a profit for the first time in 2007 and was ranked in June 2009 as the 6th most valuable social networking site in the world.

8. www.Orkut.com (67m Users)

Orkut is another general social networking site and is owned by Google. It is named after its creator, Google employee Orkut Buyukkokten, and has achieved some great success in India and Brazil; with 49.83% of its users being from Brazil as of May 2009. A further 17.51% of its users are from India. The site was originally operated and launched from California before Google announced that the site would be fully operated by Google Brazil from August 2008. Orkut was also once very popular in Iran before the state blocked almost all international communities in a censorship drive. Saudi Arabia has also censored the site.

9. www.Flixster.com (60m Users)

Flixster is a movie specific social networking site which is focused on the sharing of movie reviews, movie ratings, and pairing people with others with similar movie tastes. Flixster was founded in June 2005 and experienced a huge burst of growth at the end of 2006 when daily page views rose from around 20 million per day to 50 million per day in just three months, a figure with has since declined significantly again. The site is however a shadow of its former self, with Quantcast estimating that the number of global daily page views had dropped to just 1.3 million by mid 2008. Flixster has however been able to capitalise on the growth of Facebook, with its Facebook app 'Movies' consistently being one of the most popular on the site with around 400,000 daily users in July 2008. Its Myspace application has had equal success, with over 4 million users. It has also released an iPhone application which allows people to access movie reviews and trailers on the go.

10. www.Netlog.com (54m Users)

Netlog was formally known as Facebox and Bingbox and is a Belgian social networking site, it was specifically aimed at the youth demographic in Europe and caters for 25 different languages, as of September 2009 it had 54 million registered users. Netlog users can create their own web page, publish music play lists, share videos and join groups. It is particular popular in central Europe (but not the UK or Ireland), Turkey, Quebec province in Canada, and in parts of the Arab world. The site is open to anybody over the age of 13.