Syria's civil war has led to a new, greater threat of Islamist radicalism in Saudi Arabia that requires a more aggressive "war of ideology" on the Internet, says the man responsible for online monitoring in the kingdom.
Remarks by the head of the Saudi Ideological Security Directorate (ISD) suggest that the unit, known for keeping tabs on liberal activists and women drivers as well as Islamist extremists, is turning its focus increasingly towards those using the Internet to recruit fighters for jihad abroad.
This month King Abdullah decreed that any Saudi who goes overseas to fight faces jail terms of 3-20 years. Authorities believe 1,000-2,000 of the kingdom's citizens have gone to Syria to join the war there.
The decree also imposes punishment on Saudis who join, glorify or give moral or material support to groups described as terrorist or extremist, a list that has not yet been published.
From an office near a firing range in a police academy in Riyadh, the ISD keeps tabs on "anything that might influence the stability of Saudi Arabia," said its director, Abdulrahman al-Hadlaq. That broad mandate includes peaceful political or human rights activists, he said. Several have been jailed over the past year on charges that included comments made online.
"Our job is to counter radicalisation - either conservatives or liberals," he told Reuters in an interview.
The directorate monitors online activity, reports threats to the security services and participates on social media to rebut arguments of Islamist militants speaking in favour of jihad.
Hadlaq justified the policy by saying most governments, including those in the West, monitor citizens online. The Saudi monitors are careful to distinguish between people who simply voice opinions and those who incite others to action, he said.
Three years after the Arab uprisings and facing a bitter rivalry with Iran being played out on the battlefields of Syria, and in Bahrain, Yemen, Iraq and Lebanon - Saudi Arabia's rulers feel more threatened than ever.
Saudi Arabia is one of the main sources of arms and cash for rebels fighting against Iran's ally Bashar al-Assad in Saudi Arabia. But it has increasingly been worried about a blowback at home as al Qaeda-linked fighters gain influence, much as Saudi Arabia faced a threat from returning fighters from Afghanistan and Iraq who killed hundreds in a bombing campaign before being crushed last decade.
It is imperative that Saudi Arabia fight a "war of ideology" online, Hadlaq said. "If we don't do this, terrorists will come back and the terrorism issue will come back."
"Before the problems in Syria started, the role of Qaeda and the radicals were declining," Hadlaq said. "When the issue of Syria came and the guys started watching the brutality of the system there and the regime in Syria, we started noticing that radicalisation might come back."
Saudi Arabia's few liberal activists worry that they are targeted by the same body that deals with terrorism.
Saudis are among the world's biggest users of social media, using it to discuss political, religious and social issues that were once seen as taboo. Many quietly grumble about what they see as heavy-handed interference by the authorities.
Comments counter to government policy are quickly attacked by what users have come to refer to as "Saudi eggs" - suspected government officials represented by the egg that Twitter uses as the default image for users without profile photos.
Hadlaq said most of the people who argue on the government's behalf online are "volunteers" and many are doing so without the help, guidance or even knowledge of the authorities.
Those who argue against militant Islamists "are really doing a good job, posting and replying to those extremists," he said.
Government monitors use a guidebook and database of arguments to counter militant rhetoric online, he said.
"We have a huge guide that is really a reference for us... We have a database and we use it to refute. For example if someone says 'I can go (on jihad) without taking permission from my mother', we have an answer for this," he said. Riyadh has shared this database with Western governments, he added.
Over the past three years, the government has stepped up its campaign against all groups that challenge the authorities, including human rights and pro-democracy advocates who have been detained and imprisoned.
Last year the political and human rights activists Mohammed Fahd Qahtani and Abdullah al-Hamad were jailed for more than 10 years, partly because of social media posts, including one that called for the then interior minister, the late Prince Nayef, to be stripped of his job and charged with rights abuses.
Blogger Hamza Kashgari was imprisoned for more than a year after posting tweets of a hypothetical conversation with the prophet Mohammad, ruled as blasphemous.
Among other possible targets, Hadlaq said, could be the Muslim Brotherhood, the pan-Arab Islamist group which came to power in Egypt after the 2011 revolution there until it was overthrown by the military last year.
In a sign of rare Saudi political ferment in recent months, some Saudis have begun using as their online avatars a four-fingered salute adopted as symbol by the Brotherhood after protesters were killed in a Cairo square last year.
"Followers of the Muslim Brotherhood would be considered illegal, because the laws here are really against any creation of a political group," Hadlaq said. The Brotherhood had pushed "issues that are in contradiction with the Saudi policies".
Use of the four-fingered sign on the Internet was being watched, but for now was considered more of a sign of sympathy with slain protesters than proof of illegal support for the Brotherhood's aims, Hadlaq said.
In addition to monitoring the Internet, the ISD is also responsible for running the kingdom's rehabilitation programme for militants, oversees an anti-militancy publicity campaign and works to counter radicalisation among clerics and teachers.
When it is concerned about somebody online it passes the information to an investigative security branch.
"Sometimes you will report an issue on someone that from monitoring him you think he is dangerous. Then in a few days or weeks you will be seeing him taken to court," said Hadlaq.
Hadlaq added he thought there were "tens" of Saudis now under investigation or in a legal process because of comments written on social media. Most people being watched in the kingdom are "sympathisers" rather than actively involved with radical groups, he said.
The new decree imposing prison terms for those who go abroad to fight or are aligned with groups the government sees as extremist will make the ISD's job easier, he added.
"Now you have a special law that really prosecutes, or helps you prosecute, people in a very clear way. I think this is important. We already noticed (online extremism) declining."
He defended the government's policy of viewing liberal activists, including those calling for women being allowed to drive, as potentially dangerous.
"The policy of Saudi Arabia, we want a united society. We don't want things to influence our unity. So if something is going to make our society unstable or disunite out society, we will pay a lot of attention to it," he said.
A woman who participated in a women's driving campaign in October by filming herself behind the wheel and posting it on YouTube, as well as with Tweets encouraging others to do the same, said she had reduced her social media profile.
Although she was not contacted by the authorities, she was worried that her online posts could make her a target.
"I think it's wrong. Women's driving is not a threat to the government but they always mix everything together and accuse people of making a threat. After what happened to some tweeters, I locked my account. It's so private right now that I only have 34 followers," said the woman, who asked not to be identified.