The mobile app Tumblr is less popular than some other social media sites, but it's the source of some viral Brexit posts that have really stirred up millennials. Getty Images

Young people in Britain are not happy with voters' recent decision to leave the European Union, so they're fighting back — on Tumblr.

Ever since the Britons voted narrowly in favor of the so-called Brexit last week, users have flooded the image-based blogging platform with text posts aimed at explaining to their international peers what's going on in Britain. A Tumblr spokeswoman told International Business Times that between Wednesday and Saturday, the site saw more than 1.5 million posts under the hashtag #Brexit.

The trend makes sense: Tumblr is dominated by young people, to the extent that about half of its 19.1 million users last year were between the ages of 18 and 34, according to Adweek. In the U.K. referendum Thursday, about three-quarters of people under 25 voted to remain in the European Union.

The consequences of a Brexit will take a while to unfold, but the Guardian predicted it may hurt university funding, limit where youth can work, and launch a recession. An opinion piece published in Vox put it more bluntly, labeling the results of the EU referendum "a final middle-fingered salute to the young from the baby boomer generation."

It's de rigeuer for the younger generation to react to every news event on social media, but they mostly use services like Snapchat, Twitter and Instagram, whereas Tumblr is used by only about a tenth of online adults. That means young Britons' decisions to air their concerns on the blogging site have started drawing notice among international media sites.

The Brexit protesters are using easy-to-understand language, internet slang and memes to transform their blogs into political forums as a form of protest against the vote. And their online friends around the world are responding, reblogging, liking and commenting in droves. (This post about Brexit facts, for example, has been shared or liked more than 150,000 times.)

Read six other popular #brexit posts below:

1. “No one has a plan.”

Brexit, explained in bullet points. screenshot / Tumblr

2. "Britain gave in to the racist and xenophobic rhetoric."

A Tumblr post urges readers to vote for Democratic presidential candidate Hillary Clinton over presumptive Republican nominee Donald Trump. screenshot / Tumblr

3. "URGH."

A pre-Brexit post lays out the pros and cons of the vote. screenshot / Tumblr

4. "My [immigrant] mum is freaking out."

A user explains her personal experience with Brexit. screenshot / Tumblr

5. "The world is Not Quite Right."

A Tumblr user compares 2016 to fiction. screenshot / Tumblr

6. "This is fine."

This GIF accompanies a post about the Brexit. screenshot / Tumblr