Spybot was intended to be an open system from the beginning. When Patrick was called by his university that his software was now using a third of the bandwidth of the whole institution, he had a great discussion with the computer science department and decided to provide Spybot as what was regarded as open source back then. While this does not fully fit todays definition of open source, Team Spybot published, along with the release of Spybot 1.6, an open format describing how to detect malware: OpenSBI.
OpenSBI has a simple format to describe not just files, but dozens of system entity types, and Spybot includes a syntax highlighting editor to simplify its use. Additional tools like FileAlyzer create parameters in OpenSBI format as well, allowing everyone to enhance Spybot with individual signatures.