Your readers have a common interest - your blog’s subject. My readers are preparing for the Law School Admissions Test (LSAT). Maybe yours are interested in knitting, running, or making money online. Just as they have subscribed to your blog, they will join your Facebook group.

At the beginning of December 2008, I created the 2009 LSAT Study / Discussion Facebook Group. Someone else had created a 2008 LSAT Group, and I wanted to be the person to create the 2009 group, so I started early. When someone is searching Facebook for an LSAT group to join this year, they’ll see my group has over 100 members, but someone else’s group on the same topic only has 3, guess which group they’ll join.