A mother on a local mom's group we belong to sent out a link to a news investigation that found many baby monitors allow strangers to see right into your home.
Because the monitors use public airwaves, it's possible for anyone with a monitor driving by your house to pick up your signal and see and hear your baby clearly. If you have a monitor on you while you nurse your child to sleep or in your own bedroom, this is certainly worth thinking about. Apparently, you won't encounter this problem with the newer digital monitors.
You can watch the full report here.