Facebook may hit 1 billion users this summer, but overall social market share is becoming more diluted which should emphasize the importance of focusing on the needs of your most engaged fans.

Marketing Land has outlined a new study from Pew Interactive that gives new credence to the 80/20 rule. In the study, Pew surveyed 269 Facebook users and obtained information on their Facebook account to confirm the responses.

Most of your Facebook fans don't interact very much but the ones that do are vital to overall engagement. They are sharing your content, liking your pictures and commenting on a regular basis. Understanding how they interact with your brand can help you develop strategies that improve overall fan engagement moving forward.

Facebook power users are adding more friends, averaging about 8 per month, with men sending out more requests and women receiving more of them overall.

In addition, power users "like" more Facebook content than the majority of users. According to the study, approximately 1/3 of respondents used the like button once a week and 37% of respondents had their own content liked. The most engaged 5% of users link content over 100 times each month.

There's a reason Facebook might be testing private messaging between Fans and brand pages. According to the Pew Interactive study, the frequency of Facebook messaging use meant almost double their application of the "like" button.

About 20% of users in the study commented on a post every day and about 55 commented 100 times or more per month. The average Facebook user commented on posts much less often.

Perhaps the most important revelation in the study concerned the social reach of the average person on Facebook.