Originally the RegulomeExplorer was written using a library called protovis.js. Later, d3.js was released, providing a means to have much better rendering performance in the browser and the ability to structure the code more cleanly.
The ideogram layout is derived from the work of Edward Tufte in the book Visual Display of Quantitative Information. Martin Krzywinski applied it to genetic expression data, creating the beautiful Circos tool. That tool generated raster images, making it less suitable for interactive exploration on the web.
This project was an effort to bring some of the usefulness of that rendering to the web and connect it to large genetic datasets and the downstream analysis derived from them.
Anything you like. Though the usefulness of the ideogram layout is not suitable for every type of data, it is useful in positioning data based on the position of the genes on chromosomes. Other data (eg. mRNA, SNP) is layered into the ideogram, as desired.
Yes. In fact it was featured as part of the keynote (on Day 2) of Google IO conference in 2012 to demonstrate the power and scale of the new Google Compute Engine. In the demonstration, given by Urs Holzle, a random forest model training in coordination with a feature importance calculation was performed on 600,000 cores in front of a live audience. The result of this computation was rendered via CircVis.
The video linked below is the talk. After watching for a few minutes, skip from 42:30 to 45:50 for the big finale!