Couldn’t find any info on how long the sign-ups are open for, but it looks like they might’ve been open for a while now judging by the date of this Reddit post:
https://www.reddit.com/r/OpenedSignups/comments/1irq5nu/arabp2p_open_signups/
For those interested, here is the content they allow (via machine translation from Arabic):
Video: Islamic - Documentary (dubbed - translator) - Educational (dubbed - translator) - Arabic films - Indian films (translator) - Asian films (subtitles) - Asian films (subtitles) - Ramadan - Arabic series - Asian series (dubbed - translator) - Plays
My voice: the Holy Quran - Lectures - Songs
Books: Arabic books only
Programs: Arabic programs only (not Arabic), excludes Adobe versions supporting the Arabic language and Microsoft versions
Anime: Translator and Arabic dubbed only