It is interesting to browse through the top websites as assessed by Alexa here: TOP Sites
Eleven of the top 100 websites are social media sites. (I have also included an estimate of recent total monthly visitors, when I found a credible estimate somewhere else on the web.)
Note that blogging is understated because it is not dominated by a social site. For example, according to WordPress there are more blogs using WordPress software on a private site than using the WP blog hosting site that is used in this ranking.
The top eleven ranked by Alexa:
Platform(s) Social Media Monthly Visitors Alexa Rank[2]
- Facebook Social Network 850 million 2
- YouTube Video-sharing 800 million 3
- Twitter Micro-Blogging 250 million 9
- LinkedIn Professional Network 110 million 14
- Google+ Social Network 100 million —
- WordPress Blogging — 22
- Tumblr MicroBlogging 13 million 36
- Pinterest Social Scrapbook 11 million 38
- Blogger Blogging 47
- Flickr Photo Sharing 56
- Instagram Photo Sharing 98
[1] Wikipedia estimates (October 2012) unless otherwise cited; the sites are ranked by the Alexa ranking for consistency
[2] Alexa web site rankings at http://www.alexa.com/siteinfo World Ranking
[3] Top 15 social network sites, October 2012, eBizMBA http://www.ebizmba.com/articles/social-networking-websites
Social Media Marketing 4 Business 
Hey Gary Schirr,
Very interesting, I want to create a social media site ( facebook,myspace…ETC.). I have a background in Freelance Web and graphic design and I have some pretty good ideas. I’m looking for someone to possibly partner up with.
Wishes