Here are all the major US tech companies blocked behind China's 'Great Firewall'

Includes: YouTube, Gmail, Google Play, Google Maps, Google Drive, Hangouts, Blogger

When it was first blocked: YouTube was blocked on-and-off multiple times in the late 2000s, including in October 2007, March 2008 during riots in Tibet, and in March 2009 when it went down in the country for good.

Particular queries on Google, including those related to politics, have long been censored in China. Google.cn, the company's China-based search engine, was shut down in 2010 following disputes over censorship of search queries. Google's family of apps — including Gmail and Google Maps — have went offline multiple times, including in November 2012 and December 2014.

Reports emerged in 2018 that Google was working on a censored search engine for Chinese users called Project Dragonfly. The project was reportedly cancelled in December after facing outrage from Google employees and human rights groups, but some activists are not fully convinced Google has officially scrapped plans.

Includes: Periscope

When it was first blocked: June 2009, shortly before the 20th anniversary of the Tiananmen Square protests in 1989, when the Chinese army killed hundreds of students demanding democracy.

Despite the ban, Twitter still has an estimated 10 million active users in China, who use VPNs to circumvent the ban.

When it was first blocked: It's unclear when Snapchat was initially banned in China, but the social platform does have a small office in the country to work on Spectacles, Snap's camera-equipped smart sunglasses.

When it was first blocked: August 2018, although many Redditors were more surprised the site hadn't been banned earlier.

When it was first blocked: May 2016, although pages containing political and pornographic content have been heavily censored in China before then.

When it was first blocked: March 2017, around the time when China was hosting its annual "Two Sessions" political gathering.

When it was first blocked: The timeline of when Slack was first blocked in China is not clear, but access to the messaging app has been "somewhat inconsistent" for years, according to the company itself.

When it was first blocked: September 2018, after app downloads skyrocketed for those in China who wanted to catch e-sports matches at the 2018 Asian Games.

When it was first blocked: Reports first surfaced in mid-2018 that users of the popular chat app for gamers were unable to access the service in China.

When it was first blocked: May 2010. Access to Dropbox was temporarily restored in February 2014, but its website and apps were blocked again in China by that June.

When it was first blocked: The popular Q&A site was first blocked in China in August 2018.

When it was first blocked: The blogging site was unavailable in the country from April 2016.

When it was first blocked: Wikipedia's Chinese-language edition has been blocked for good since 2015, but China barred all language versions of Wikipedia more recently: this May.

When it was first blocked: The video site went down in China pretty early, in October 2009.

When it was first blocked: The photo site went behind the "Great Firewall" in June 2007, just a few years after Yahoo bought it. Nowadays, SmugMug owns Flickr, but it doesn't appear like the site's situation in China has changed at all.

When it was first blocked: The music-sharing service was first blocked in September 2013. Since then, it's been blocked in China intermittently, including in May 2015.

When it was first blocked: The privacy-focused search engine was blocked in September 2014.

When it was first blocked: Like several popular video-sharing sites, Dailymotion is blocked in China, although it's not clear when it went into effect.