Enabling it will allow other administrators to know that you are mainly federating sensitive content.<x id="LINE_BREAK" ctype="lb" equiv-text="<br />"/><x id="LINE_BREAK" ctype="lb" equiv-text="<br />"/> Moreover, the NSFW checkbox on video upload will be automatically checked by default.
You can import any URL <x id="START_LINK"/>supported by youtube-dl<x id="CLOSE_LINK"/> or URL that points to a media file. You should make sure you have diffusion rights over the content it points to, otherwise it could cause legal trouble to yourself and your instance.