I’ve often stated that for the most part you shouldn’t build your community on platforms where you have no control.

As Socialfresh points out, Facebook has tweaked things and a Brand’s Page Reach has been negatively impacted.

My team at EdgeRank Checker released a quick study looking at how Pages have been impacted by this suspected change if you want to read more about the shift.In summary, we found that organic reach is down 25 percent, viral reach is down 45 percent, and engagement decreased 17 percent, while virality marginally increased 7 percent.

Without any action on your part, engagement dropped 17%. If you controlled the community platform and this happened, you could take action and attempt to fix things.

via How to Diagnose and Survive the Current Facebook Reach Drought.