Watch this short video describing this feature:
On the other computer, go to a Notezilla sticky note , select the "Send To->Computer " option and select a computer from the list. This will open the firewall (show message) on that computer.
After this you can come back to the first computer and try sending the Notezilla sticky note via the IP address.
Yes, that's right. Notezilla needs to be running on each computer on a network.