This came up in comments on this question.
Since before the Internet was widely available, it's been common to pass along files received from other users or downloaded from a server somewhere. For amateur radio, however, the FCC has some rules concerning "third party communications", where Alice sends a message to Bill on behalf of Charlie, who isn't part of the communication (for purposes of this question, Charlie isn't under a license revocation).
If I send a downloaded file (one I didn't create) via a digital connection such as a mesh network, would this constitute "third party communication"? I have the file already stored in my local system; I'm not downloading it from a server in real time as I transmit to the mesh. I'm not being paid for the file, either as a condition to sending it, or on approval (like the old "shareware" concept). All I get out of the exchange is a good feeling for sharing something I've enjoyed, and the likelihood that someone else on the mesh will share something I might want.
With no "fiduciary interest" this ought to be legal (pending copyright etc. concerns), but does it in fact constitute "third party communication"?