Facebook’s business model is built around sharing data about its users - sharing it with other users and with advertisers. For all the openness around the social network, some of the data points that become available about the users can be surprising.

For example, according to Hubspot some of the least popular page types on Facebook are local businesses. In other words, page types that have fewer fans than the average page - which is 624 - are real estate professionals (a local business) local automotive deals and local professional services. Also, as companies struggle to determine the dollar value of a fan, they are finding that lower paid workers may be of higher value on Facebook, according to Business Insider.  It recently developed a chart showing that, while an average Goldman Sachs employee is paid $500,000 and the average Wal-Mart employee salary is $20,000, "in the eyes of an advertiser, a Wal-Mart employee is worth nearly twice as much as a Goldman employee, according to Facebook's suggested advertising bid prices."

Venture Beat also looked at these bid prices and developed other metrics about Facebook's users, based on its annual revenues of $800 million last year.

• Facebook users in the United Kingdom are the most expensive to reach, while Italian and Japanese users are the cheapest.

• Older users are more expensive to reach than younger users.

• Facebook users that are interested in or like CNBC are more expensive to reach than users who like other media brands.