Software developers use many different communication tools and channels in their work. The diversity of these tools has dramatically increased over the past decade and developers now have access to a wide range of socially enabled communication channels and social media to support their activities. The availability of such social tools is leading to a participatory culture of software development, where developers want to engage with, learn from, and co-create software with other developers. However, the interplay of these social channels, as well as the opportunities and challenges they may create when used together within this participatory development culture are not yet well understood. In this paper, we report on a large-scale survey conducted with 1,449 GitHub users. We discuss the channels these developers find essential to their work and gain an understanding of the challenges they face using them. Our findings lay the empirical foundation for providing recommendations to developers and tool designers on how to use and improve tools for software developers.

Software ecosystems as a paradigm for large-scale software development encompass a complex mix of technical, business, and social aspects. While significant research has been conducted to understand both the technical and business aspects, the social aspects of software ecosystems are less well understood. To close this gap, this paper presents the results of an empirical study aimed at understanding the influence of social aspects on developers' participation in software ecosystems. We conducted 25 interviews with mobile software developers and an online survey with 83 respondents from the mobile software development community. Our results point out a complex social system based on continued interaction and mutual support between different actors, including developers, friends, end users, developers from large companies, and online communities. These findings highlight the importance of social aspects in the sustainability of software ecosystems both during the initial adoption phase as well as for long-term permanence of developers.

Researchers are currently drawn to study projects hosted on GitHub due to its popularity, ease of obtaining data, and its distinctive built-in social features. GitHub has been found to create a transparent development environment, which together with a pull request-based workflow, provides a lightweight mechanism for committing, reviewing and managing code changes. These features impact how GitHub is used and the benefits it provides to teams' development and collaboration. While most of the evidence we have is from GitHub's use in open source software (OSS) projects, GitHub is also used in an increasing number of commercial projects. It is unknown how GitHub supports these projects given that GitHub's workflow model does not intuitively fit the commercial development way of working. In this paper, we report findings from an online survey and interviews with GitHub users on how GitHub is used for collaboration in commercial projects. We found that many commercial projects adopted practices that are more typical of OSS projects including reduced communication, more independent work, and self-organization. We discuss how GitHub's transparency and popular workflow can promote open collaboration, allowing organizations to increase code reuse and promote knowledge sharing across their teams.

The microblogging service Twitter has over 500 million users posting over 500 million tweets daily. Research has established that software developers use Twitter in their work, but this has not yet been examined in detail. Twitter is an important medium in some software engineering circles—understanding its use could lead to improved support, and learning more about the reasons for non-adoption could inform the design of improved tools. In a qualitative study, we surveyed 271 and interviewed 27 developers active on GitHub. We find that Twitter helps them keep up with the fast-paced development landscape. They use it to stay aware of industry changes, for learning, and for building relationships. We discover the challenges they experience and extract their coping strategies. Some developers do not want to or cannot embrace Twitter for their work—we show their reasons and alternative channels. We validate our findings in a follow-up survey with more than 1,200 respondents.

With over 10 million git repositories, GitHub is becoming one of the most important source of software artifacts on the Internet. Researchers are starting to mine the information stored in GitHub's event logs, trying to understand how its users employ the site to collaborate on software. However, so far there have been no studies describing the quality and properties of the data available from GitHub. We document the results of an empirical study aimed at understanding the characteristics of the repositories in GitHub and how users take advantage of GitHub's main features---namely commits, pull requests, and issues. Our results indicate that, while GitHub is a rich source of data on software development, mining GitHub for research purposes should take various potential perils into consideration. We show, for example, that the majority of the projects are personal and inactive; that GitHub is also being used for free storage and as a Web hosting service; and that almost 40% of all pull requests do not appear as merged, even though they were. We provide a set of recommendations for software engineering researchers on how to approach the data in GitHub.

There are many different approaches to testing software, with different benefits for software quality and the development process. Yet, it is not well understood what developers struggle with when getting started with testing - and why some do not test at all or not as much as would be good for their project. This missing understanding keeps us from improving processes and tools to help novices adopt proper testing practices. We conducted a qualitative study with 97 computer science students. Through interviews, we explored their experiences and attitudes regarding testing in a collaborative software project. We found enabling and inhibiting factors for testing activities, the different testing strategies they used, and novices’ perceptions and attitudes of testing. Students push test automation to the end of the project, thus robbing themselves from the advantages of having a test suite during implementation. Students were not convinced of the return of investment in automated tests and opted for laborious manual tests - which they often regretted in the end. Understanding such challenges and opportunities novices face when confronted with adopting testing can help us improve testing processes, company policies, and tools. Our findings provide recommendations that can enable organizations to facilitate the adoption of testing practices by their members.

The multitude of social media channels that programmers can use to participate in software development has given rise to online developer profiles that aggregate activity across many services. Studying members of such developer profile aggregators, we found an ecosystem that revolves around the social programmer. Developers are assessing each other to evaluate whether other developers are interesting, worth following, or worth collaborating with. They are self-conscious about being assessed, and thus manage their public images. They value passion for software development, new technologies, and learning. Some recruiters participate in the ecosystem and use it to find candidates for hiring; other recruiters struggle with the interpretation of signals and issues of trust. This mutual assessment is changing how software engineers collaborate and how they advance their skills.

Many software development projects struggle with creating and communicating a testing culture that is appropriate for the project's needs. This may degrade software quality by leaving defects undiscovered. Previous research suggests that social coding sites such as GitHub provide a collaborative environment with a high degree of social transparency. This makes developers' actions and interactions more visible and traceable. We conducted interviews with 33 active users of GitHub to investigate how the increased transparency found on GitHub influences developers' testing behaviors. Subsequently, we validated our findings with an online questionnaire that was answered by 569 members of GitHub. We found several strategies that software developers and managers can use to positively influence the testing behavior in their projects. However, project owners on GitHub may not be aware of them. We report on the challenges and risks caused by this and suggest guidelines for promoting a sustainable testing culture in software development projects.

GitHub projects attract contributions from a community of users with varying coding and quality assurance skills. Developers on GitHub feel a need for automated tests and rely on test suites for regression testing and continuous integration. However, project owners report to often struggle with implementing an exhaustive test suite. Convincing contributors to provide automated test cases remains a challenge. The absence of an adequate test suite or using tests of low quality can degrade the quality of the software product. We present an approach for reducing the effort required by project owners for extending their test suites. We aim to utilize the phenomenon of drive-by commits: capable users quickly and easily solve problems in others' projects - even though they are not particularly involved in that project - and move on. By analyzing and directing the drive-by commit phenomenon, we hope to use crowdsourcing to improve projects' quality assurance efforts. Valuable test cases and maintenance tasks would be completed by capable users, giving core developers more resources to work on the more complicated issues.

It is poorly understood how developers discover and adopt software development innovations such as tools, libraries, frameworks, or web sites that support developers. Yet, being aware of and choosing appropriate tools and components can have a significant impact on the outcome of a software project. In our study, we investigate link sharing on Stack Overflow to gain insights into how software developers discover and disseminate innovations. We find that link sharing is a significant phenomenon on Stack Overflow, that Stack Overflow is an important resource for software development innovation dissemination and that its part of a larger interconnected network of online resources used and referenced by developers. This knowledge can guide researchers and practitioners who build tools and services that support software developers in the exploration, discovery, and adoption of software development innovations.

Software engineering research and practice provide a wealth of methods that improve the quality of software and lower the costs of producing it. Even though processes mandate their use, methods are not employed consequently. Software developers and development organizations thus cannot fully benefit from these methods. We propose a method that, for a given software engineering method, provides instructions on how to improve its adoption using social software. This employs the intrinsic motivation of software developers rather than prescribing behavior. As a result, we believe that software engineering methods will be applied better and more frequently.