Without going too much into details, I work in cyber security and we use graph db to store control flow graphs of modules/binaries that we disassembled using IDA/IDAPython. We use the information to filter out "interesting" functions when conducting a research that spans across versions of the same product.
I'm residing outside the US, where iPhones cost a lot more and the new models are available 2-3 months after the release day.
I use that 2-3 months gap to buy my new phone abroad and sell my old phone to somebody while there's a demand. I recently upgraded to iPhone6 and sold my iPhone 5 for ~$400 (USD), so essentially I paid $300 for the new phone.
I'm an adviser for one of the companies that partnered with VirusTotal. I cannot go too much into details, but as a partner, we have access to the live submission feed which we analyze in real-time to discover new threats etc. I can assure you that we are not the only one. Furthermore, most partners sync their data not in real-time which could yield incorrect scanning results, making the hackers think they're good to go.
I can also say that the more serious groups/hackers do not use VirusTotal to check their malware. They have their own verified, anonymous services that do the same thing, just without submitting the malware to the anti-virus company.
I guess the chart is designed to those who are doing their first steps in the machine learning world. It makes order.
BTW I have nothing to do with scikit-learn, I shared it as I found it to be useful.