Lovely! Nothing seems to happen when I click "Download Large Graph".
Added to https://iris.to and https://graph.iris.to the option to download a large pre-crawled social graph with 161K users and 5.25M follow relationships.
Discussion
There's no download indicator but it should be downloading https://files.iris.to/large_social_graph.json. You can also try downloading from that link and feeding to "load from file".