When Facebook went IPO in May they Launched a new feature: Facebook Promoted Posts
You may be wondering about this feature and why now your posts are not reaching all your fans, Right? Well, Facebook has been trying to make those aware that not much has changed and Facebook posts have always just been seen by a portion of your audience.
You have to be aware that not everyone is online at the sametime of your posts or they may have a lot of friends and activity in their newsfeed for your posts to show up, so therefore not much has really changed.
This new feature is just a way to push your posts more prominently into fans newsfeeds.
Mash-Up gives a good Step by Step guide on Facebook Promoted Posts See Here: http://mashable.com/2012/05/31/facebook-promoted-posts-tips/