system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does Grooveshark play whatever song you want for free while Pandora requires you to listen to radio stations with mandatory commercials?
gpt
Pandora operates completely legitimately, while Grooveshark technically does not.  Grooveshark has been involved in the occasional lawsuit, and more will likely come.  Its more a matter of the fact that Grooveshark has remained more under the radar, and with so many different sources of what may be called copyright infringement on the internet, it takes massive popularity for one roll into the spotlight enough so that it is targeted specifically by the RIAA or whoever else may be involved.