What is the ruling on mixed da'wah groups on Facebook and WhatsApp, and does the ruling differ if women are only followers without participating?

Direct conversations and communications between unrelated men and women online, whether spoken or written, are a gateway to fitna (temptation/discord) and evil, because they lead to a leniency that results in admiration and corrupting attachment. The Sharia has blocked all doors leading to fitna. As for a woman's participation in scholarly or da'wah (preaching) groups, it is permissible, provided there is strict adherence to Islamic etiquette and complete seriousness, and the door to fitna is blocked. This includes not publishing anything that incites desires, limiting comments to what is necessary, leaving the group immediately after asking a question, avoiding soft speech and joking, and refraining from private messaging, keeping in mind that nothing equals safety.