One of the most effective aspects of Facebook's advertising platform is the ability to target users by demographic, geography and even "likes". Advertisers have become quite efficient at crafting and targeting campaigns for these parameters. Some of those targeting tools are available to Facebook Page owners as well... but it isn't as widely known / utilized. Here is an example: I posted to @dogpatchlabs an upcoming event hosted by Recurly (a Dogpatch graduate). The event is based at their San Francisco headquarters... so Facebook gives me the option of sharing that post only with local fans.
This is quite powerful - particularly for brands with huge followings (ie the NBA and local games / highlights, Art.com with local art, etc).
And as Facebook continues to evaluate engagement rates as the core element of Edge Rank, this is a chance to make sure you are effectively connecting with your audience.