3. Contributing to virus propagation and exposing oneself to the risk of contamination

Most viruses are carried by infected files exchanged by users. Such viruses exploit the vulnerability of specific applications or security breaches of specific operative systems to execute malicious code.
Virus proliferation in these cases relies on the fact that the majority of users use the very same kind of software and share data in the native (=proprietary) format of such software. Most viruses are hence not only platform-specific but also application-specific: in many cases, simply switching to a different application makes a system immune against a class of viruses (see for instance the large number of MSWord-macro viruses). Using open formats - data formats that are software-independent, interoperable and accessible on different platforms - weakens the overall impact of viruses and discourages their propagation: it is extremely easier to create a virus exploiting known vulnerabilities of a single, largely used software and the lack of awareness of users, than adding malicious code within a format that can be read by a large number of applications and on different kinds of platforms.