The upper left of the SVG is empty (blank or white) so if your viewport is relatively small then you will be looking at a white page.
Did you try scrolling? It's a comment thread rendered as a graph; the root comment is in the top center.
Interestingly, most of the threading WWW discussion fora, and threaded mail/news readers that I've encountered start such diagrams in the top left hand corner.
Sounds like an incredibly poor think to post to HN, even if it may be possible to find germane content somewhere in the SVG.
You have to scroll to the right
I had to zoom out to 25% of the original zoom level to see anything.
It's a big, sprawling conversation, and the SVG gives a way to see the extent of it before you click on any of the nodes to dive in to the bit you're interesting in.