At my first full time software development job, the company I worked for had a telemarketing B2B call center. It was run by a web application that controlled the agent's phone via some ActiveX TAPI components. I modified the software so it could work with Skype, so the company could open new offices without having to set up some crazy expensive phone system. The company was happy but I'm sure I helped inconvenience and annoy countless people. I'm sure there's a similar story behind plenty of the more modern forms of this like robocalls and phone number spoofing.
