d45f731d_Pages__and_5_That_Do____Gigaom__Benefits_to_You
[Reason] 1. They genuinely like or are interested in the object of the Page (company, nonprofit, cause, campaign, product, brand, etc.) [Interactions on Page] High [Benefits to You] 
Many, including branding, customer service, relationship building, attracting attention, growing customer base.
5 Things That Don't Work on Facebook Pages (and 5 That Do) | Gigaom
Benefits to You