It would be nice if we could import and export graphs in JSON node-link format per:
The question is: What software uses this specific format? Is it widely used?
It shouldn't be difficult to produce JSON form an igraph graph with any of the high-level interfaces. With Mathematica it was just a few lines even 3 years ago and now it should be simpler still.
There are many different ways to encode a graph into JSON. Does it make any sense to create an exporter just for one type of representation unless it is widely used by many different tools?
This is the most flexible format for import/export in the very popular Python graph library, NetworkX.
Is it fully documented anywhere? Is there any other software than NetworkX which uses this specific encoding into JSON?