The podcast Reply All, hosted by PJ Vogt and Alex Goldman, decided to let fans call their cell phones for 48 hours straight, expecting around 10,000 calls but receiving over 105,000. The team needed an engineer to build a system that could handle the high volume of calls, which was successfully done using Twilio's technology. However, they encountered unexpected issues such as two callers being connected to each other instead of the hosts, and they had to rely on their community for help in resolving these edge cases. Despite the challenges, the team reported many heartwarming conversations with fans, including some intimate discussions about relationships and personal struggles. The experience allowed them to build a deeper connection with their audience and demonstrated that even with large numbers, human interaction can be incredibly meaningful.