It's because Canonical spams LinkedIn with tens of thousands of job posts (despite only having ~1800 employees) because they put ads for the same remote job listing in hundreds of different cities. As a result, basically anyone who's ever looked for a tech job on LinkedIn has at least looked at the first step of Canonical's job application process (including where it asks about how well you did at math in high school, your SAT scores, your college class ranking and GPA, etc).