I had what was arguably a great phone screen. I wasn't necessarily looking for a new position but came across this job and became more interested the more I heard. At the end of the call, there seemed to be clear next steps. They were interested in me talking to more people, and will check schedules for the end of the week--what is your availability? Then radio silence. I tried to follow up a couple times and never heard anything. It's all good if things change or you're not interested, but some response, however delayed, is common courtesy.