An obsessive fan claims to have been emailing the rapper and music mogul Jay-Z for more than two years, tracking his movements using ReadNotify receipts. According to a report from BuzzFeed, the location information provided in the receipts — which are generated when the reader loads an invisible tracking image from ReadNotify's servers — matches up uncannily with the published details of Jay-Z's touring schedule, with emails having been opened from Paris, Geneva, and Manchester, from iPhones and iPads as well as desktop browsers. The emails' author, David Johnson, has never received a single reply, and has declined to reveal how he obtained what he believes to be Jay-Z's personal address — still, his bizarre hobby raises questions about the ethical status of read receipts, frequently used to harvest data in email marketing. Check out the full story of his quest for a reply over at BuzzFeed.