Sifting One's Mail

Yesterday I wrote to a security company, to pass on a contact for them to have "cheap PCB's made up". An hour-and-a-half later, by e-mail, I received an offer from a PCB manufacturer in China: "Our price is competitive." A coincidence? Here's something stranger. In November last year, an editor wrote to me that someone had, amazingly, asked if they could "still supply a Mini Lab PCB", twenty years after they had published it. I briefly corresponded with him about the Mini Lab. The same month, by e-mail, I received an offer of "spare parts, accessories" for the Mini Lab from China. That's not a coincidence. OBSERVATION: It would seem clear that people are intelligently sifting one's mail.