  Discussions is a new feature of GitHub for asking questions or discussing
topics outside of specific Issues or Pull Requests. Before being available to
all projects in December 2020, it had been tested on selected open source
software projects. To understand how developers use this novel feature, how
they perceive it, and how it impacts the development processes, we conducted a
mixed-methods study based on early adopters of GitHub discussions from January
until July 2020. We found that: (1) errors, unexpected behavior, and code
reviews are prevalent discussion categories; (2) there is a positive
relationship between project member involvement and discussion frequency; (3)
developers consider GitHub Discussions useful but face the problem of topic
duplication between Discussions and Issues; (4) Discussions play a crucial role
in advancing the development of projects; and (5) positive sentiment in
Discussions is more frequent than in Stack Overflow posts. Our findings are a
first step towards data-informed guidance for using GitHub Discussions, opening
up avenues for future work on this novel communication channel.
