How do you know?

My friend door dyke informed me that she was not going to post on her blog until I posted on mine.  How was I too know?  She did not tell me, she was just going to wait until I posted.  DD what if I never posted again?  Now the challenge is on.  I told her for every post I make, she also had to make one.  Keep an eye open and let her know if she is falling behind.