In Malaysia, preachers called ustaz or ustazah (male and female teachers in Arabic) have to be approved by the religious authority of a state or a federal body before he or she can stand before a crowd to talk in a mosque, home or hall.
One usually needs to graduate with Islamic credentials at a recognised local university, or a foreign one such as Al Azhar in Egypt, to be granted to right to publicly preach.
Still, it does not mean clerics cannot talk to the public clandestinely.
Opposition clerics from Parti Islam SeMalaysia (PAS) who speak about the religion often bypass this requirement, though most of them have graduated from the accepted universities.
The certification for Muslim preachers started decades ago, after cases of "deviant" teachings of the religion being spread in remote villages.
For mainstream TV appearances, the requirements are stricter as the stations are mostly government-linked. So one usually must be a government-friendly cleric to appear on TV shows.
Thus two of Malaysia's top Islamic speakers play to different audiences.
Ustaz Kazim Elias, seen as a pro-government cleric, appears on TV channels often. He is so popular that Prime Minister Najib Razak once invited him to join the powerful Umno supreme council, which the cleric declined.
However, a pro-PAS cleric who is just as popular, Ustaz Azhar Idrus, does not appear on TV, but his lectures on YouTube have been viewed hundreds of thousands of times.
The Internet has allowed many clerics to use YouTube or Facebook to circumvent local rules, thus aiding the spread of terrorist messages such as those by the Islamic State in Iraq and Syria.
In Malaysia, Friday sermons in most mosques are also written up by the state or federal religious authorities to ensure that the same consistent message is delivered.