You can't stop people from writing online. It's easy to regulate the press because 1) the press needs big expensive machines to print newspapers. 2) they need trucks to distribute. 3) they need shops to sell their papers. 4) they need advertisers to pay for all the above. 5) they are a business, and hence they need to make money. The government subsidizes the press both directly and indirectly. The newspaper owners would rather make money than be on the government's bad side, hence there is no freedom of press in Oman. In fact, even if the government allowed the press to write anything they want the will probably still self-censor themselves. They're not stupid to bite the hand that feeds them.
When it comes to the internet though, none of the above applies. People will say what they want and nothing will stop them. If the government shuts down Omania.net, people will find somewhere new to write. They will write in blogs. They will write in other forums. They will keep writing.
The main problem with Omania.net was that people used it for negative criticism more than anything else and they spread a lot of gossip most of which was untrue. Its administrators and moderators were extremely lax and allowed a lot of crap to flourish. More than that, it was obvious that the most active members of that forum had an agenda. They were obviously overly religious hard core ibadhi imamites, they doubted everything the government did, and for the most part they were quite racist to many of the Omani ethnic groups (in fact my family was attacked once for no reason at all). They believe that all the government's officials are corrupt. They named names and rarely ever backed it with evidence. Every single time the government announced a new project, you could bet there would be a new topic on Sablat Al Arab about it claiming that the minister behind it was making millions out of it. Who knows, it could be true, but where are the facts? Like it or not, Oman has a reputation for having a government where a lot of ministers have conflicted interest and benefit financially from infrastructure projects.
The way to counter this would be more transparency from the government, not shutting down an online forum. The average Omani is financially strapped. Unemployment is soaring and is probably in double digits but we don't know because the government never announces any negative statistics. Over 40,000 students graduate from high school every year and most of them don't go into higher education because there are no places for them. The country is in the middle of it's second biggest economic boom. The biggest since the 70's. Billions are being spent everywhere. People are getting rich, and yet the average Omani sees no benefit. Salaries have not been increased in 20 years. Do you blame them that they think every single high government official is corrupt?
Transparency. That's the need of the moment. It's been a week since the closure of Omania.net and yet I haven't seen anything about it in the press. Forget the press, we know that they'll never report about something about this, but where is the Ministry of Information? Have they not learned anything from last year's arrests whose coverage they totally mismanaged? Couldn't they have issued some sort of press release at least admitting that the government are questioning the four administrators of Omania.net and giving a brief explanation of the reason?