\section{Background}
\label{sec:spb}

Since the beginning of computing the majority of developers worked in the way
that we now identify as free software, that is, sharing code openly. This
openness makes the code available for inspection, modification, and use by any
person or organization \cite{hippel2003,kon2012}.

The elements that distinguish FOSS from other types of software are the
reasoning about the development process, the economic context, the relationship
between developers and users, as well as the ethical and legal characteristics
that relate to the software. In the context of FOSS, user freedom is promoted
and its development is based on open collaboration and development practices
\cite{meirelles2013}.

From the economic point of view, unlike what happens with proprietary software,
FOSS promotes the establishment of several suppliers that can compete with each
other based on the same software. This stronger competition among suppliers
brings benefits to users because it gives better assurances regarding the
evolution of the system and induces a reduction in prices \cite{kon2012}. These
freedoms and assurances on software are guaranteed in Brazil by Law 9610/98
(copyright law).  Most of the time, this protection from the law complies with
the terms conferred by a contract related to certain software. This contract is
called ``license''. A software license determines a list of rights that are
given to, and duties that are imposed on a user of the software. In particular,
what differentiates FOSS from proprietary software is just the way they are
licensed \cite{sabino2009}. The FOSS licenses guarantee the right to execute,
study, adapt, and improve the software. Example of common FOSS licenses  are
the \textit{GPL (GNU General Public License)}, the Apache license, the MIT
license, and the BSD license.

The original incarnation of SPB portal has been designed in 2005 and
released in 2007. From a practical point of view, it is a web system
that has consolidated itself as an environment for sharing software
projects.  It provides a space (community) for each software.
Therefore, it was designed to include tools that promote collaboration
and interaction in communities (by managers, users, and developers) of
the projects, according to the practices used in FOSS communities. This
includes mailing lists, discussion forums, issue trackers, version
control systems, and social networking environments.

Initially, the purpose of the portal was only to share the software developed
in the Brazilian government, to reduce the costs of hiring software. However,
it was observed that when softwares were released, their communities were
formed around those software with several people collaborating and sharing the
results obtained through the use of those solutions. In this way, some software
development cooperatives and private companies have shown an interest in making
their software available on the SPB platform.

The concept of Brazilian Public Software goes beyond FOSS. In addition
to being licensed under a FOSS license, a SPB needs to have explicit
guarantees that it is a public good, and that project must be available
on the SPB portal. Being a true public good assumes requirements that
can not be met solely by means of FOSS licensing. For example, there
must be a relaxed trademark usage policy by the original vendor that
does not stop eventual competitors from advertising services for that
same software. Inclusion on the SPB Portal also has extra requirements,
such as having a public version control system, installation manual, and
hardware requirements specification.

