Do you have a Facebook Page?
You may think that the more 'likers' ('Fans' as they used to be called) you have, the more outreach you have. However, this is not necessarily the case. Facebook has something called Edgerank, which determines how much of your content is actually seen on people's newsfeeds.
There are ways to improve your Edgerank - including posting more photos and videos. Your blog may be on Networked Blogs and each post is automatically posted on your FB Page as well, but you need also to post directly to the Page and in general create greater engagement.
There is a White Paper on the subject, which you can download for free here.
You can also check what the Edgerank for your Page is at EdgeRank Checker here.
How did your Page score? How do you think you can improve it?