Network effects are where the direct value of a product grows simply because the number of users increases, causing the network itself to grow. The classic example are social networks. The more people on your social network, the more people are likely to join your network and less likely to join a smaller competitor. I am not sure there is anything in Atlassian’s product offering that quite fits that description, but that isn’t to say there isn’t plenty of upsell and cross sell opportunity as you describe.