In the emails exchanged prior to my on-site interview, I usually only received a response from recruiting when I followed up again after their initial reply. My recruiter also did not show up for my scheduled phone call.

Once I arrived for the on-site interview, my schedule was intended to be from 10:15 AM to 2:15 PM, with a short lunch break in the middle. On the morning of the interview, the schedule was changed to include only a short coffee break early in the block. Consequently, I was unable to have lunch until I reached the airport, as they escort you out immediately after the interview concludes. This situation would not have been an issue had I been informed in advance, but having it change on the day itself was disappointing.

The most significant issue, however, was that the hiring manager did not show up for their scheduled interview and apparently did not communicate this absence to the recruiting team. I texted the recruiter about the no-show and did not receive a response. It appeared they were disorganized.

All of the technical phone screen and on-site interviews felt rushed. This may have been intentional, designed to place candidates under time pressure. However, particularly with the data modeling question, the time constraints forced an overly simplistic design, relying on numerous assumptions and overlooking many obvious use cases where the proposed solution would fail. I felt this approach was a disservice to individuals who are thoughtful about their work and aim to build lasting solutions.

How would you design and build a data model to report on active users and the number of posts by interface (iPad, iPhone, desktop web, etc.)?

This report should account for a hierarchy of these interfaces and their rollup groupings at any and all levels of the hierarchy.