Digital censorship, surveillance and shutdowns are increasingly common worldwide, but perhaps the most famous example is China's so-called "Great Firewall".

Here, AFP examines how the world's second most-populous country controls the internet within its borders:

- Can you use Google in China? -

The short answer is no.

The US search engine is one of many sites blocked by the Great Firewall, along with social networks such as Facebook and foreign news outlets like the BBC.

Chinese internet platforms are also required to scrub out content that the ruling Communist Party deems politically sensitive.

"The objective, in China at least, is to preserve political control, social stability, informational control, (and) ideological conformity," Shahzeb Mahmood, head of research at Tech Global Institute, told AFP.

These efforts, also called the Golden Shield Project, began in the late 1990s, when the number of Chinese internet users was rising rapidly.

As Beijing built out the firewall's sprawling architecture, further crackdowns followed, and Google pulled out of China in 2010 after rows over censorship and hacking.

- Can you jump the firewall? -

With a little help, yes. The most common way to get around China's firewall is to use a virtual private network, or VPN.

These encrypted services work by routing an internet connection through a server in a different country, allowing access to sites and apps available there.

But their use is not that widespread, said Kendra Schaefer, tech partner at research consultancy Trivium China.

"If you are a college-educated young person, and you live in a major urban area, you probably have access to a VPN, but most people don't," she told AFP.

Some mobile eSIMs can also bypass the firewall, along with phones on overseas networks set to roaming.

Beijing has largely turned a blind eye to these holes in its online censorship system.

Experts debate whether the country even has the technological capability to disable all VPN connections, Schaefer said.

- Have Chinese tech companies benefited? -

"The Great Firewall (has) acted like an incubator for Chinese tech platforms," making them more competitive against foreign rivals, Schaefer said.

Messaging apps like the near-ubiquitous WeChat, launched in 2011, and domestic search engines like Baidu have become the go-to tools for Chinese netizens.

In place of Instagram, the platform Xiaohongshu -- known as RedNote in English -- has become a popular place to share lifestyle content.

Although the firewall's main goal has been censorship, Beijing may have also considered that it would help nascent Chinese platforms develop, according to Schaefer.

Now, "if they lifted the firewall tomorrow you're not going to get an exodus of Chinese people onto Facebook -- they have better platforms", she argued.

The Golden Shield Project is no government secret, and there has been no significant pushback against it within China, Schaefer added.

- What's the appeal for Afghanistan? -

Many other Asian countries, from Vietnam and Myanmar to Pakistan and India, police their internet in similar ways.

However, the scope of the controls and their technical limitations vary. Some experts say the Taliban's methods are not as sophisticated as other governments.

"You can almost say it's a playbook that is being replicated in multiple jurisdictions, basically because it has worked in certain contexts," Mahmood said.

Afghanistan's internet and phone shutdown came weeks after the government began cutting high-speed connections to some provinces to prevent "immorality".

Mahmood said the Taliban could have several ideological reasons for wanting to control online content.

These could be "to prevent, let's say, pornography content from proliferating into Afghanistan, perhaps to stop education for women, perhaps to limit access to Western content on social media", he said.