Stack Overflow is an enormously popular question-and-answer web site intended for software developers to help each other with programming issues. Some software projects aimed at developers (for example, application programming interfaces, application engines, cloud services, development frameworks, and the like) are closing their self-supported developer discussion forums and mailing lists and instead directing developers to use special-purpose tags on Stack Overflow. The goals of this paper are to document the main reasons given for moving developer support to Stack Overflow, and then to collect and analyze data from a group of software projects that have done this, in order to show whether the expected quality of support was actually achieved. The analysis shows that for all four software projects in this study, two of the desired quality indicators, developer participation and response time, did show improvements on Stack Overflow as compared to mailing lists and forums. However, we also found several projects that moved back from Stack Overflow, despite achieving these desired improvements. The results of this study are applicable to a wide variety of software projects that provide developer support using social media.