A February 2009 study by Inside Facebook, a service dedicated to providing Facebook related research found that women over 55 were the fastest growing demographic on the social network.

Key Highlights:

* Facebook reporting nearly 45.3 million active US users in the last 30 days
* Facebook growing in every age/gender demographic. Fastest growing segment: Women over 55, up 175.3% in the last 120 days.
* Facebook growing faster with women than men in almost every age group. Women comprise 56.2% of Facebook’s audience, up from 54.3% late last year.
* 45% of Facebook’s US audience is now 26 years old or older.

More:

Overall, women now outnumber men in every age group on Facebook. In total, women now make up about 56.2% of Facebook’s US audience, up from 54.3% late last year. Women most outnumber men in the 18-25 and 26-34 age groups, where there are 1.4 females for every 1 male on Facebook.

The obvious question is, why? More from InsideFacebook.com