Content management systems, web browsers or operating systems: many of these products and services that we use every day are now implemented as open source projects. Due to the high influence that open source development has on the digital world, there are also many different statements about the advantages and dangers of open source products. Especially if you are not familiar with the subject matter, it is difficult to make a technically correct assessment of open source products The knowledge presented in this talk should help to better understand and evaluate open source software. Using this knowledge, the various dangers and advantages arising from the use of open source components can be better evaluated in the future.