By now, you've probably seen some of your Facebook friends "checking in" to the Standing Rock Indian Reservation.
Which is bizarre (and brilliant), because most of the people using the location feature on the social networking service to tag themselves at the North Dakota reservation aren't actually there.
The flood of false check-ins - around 900,000 by Monday afternoon and counting - is intended to "overwhelm and confuse" police, according to one of the viral posts that called on Facebook users to get involved.
Despite being nowhere near the protest, (plenty of Aussies have been checking in) the massive online army that continues to grow is showing its support for those in North Dakota attempting to stop the planned construction of the Dakota Access Pipeline. The controversial $3.8 billion (NZ$5.27b) investment plans to move 470,000 barrels of domestic crude oil a day across four states to Illinois.
Those in opposition argue the pipeline would endanger the water supply of the Standing Rock Sioux reservation and destroy sacred burial grounds and artefacts.
As the initiative continues to spread like wildfire, supporters on the page allege that the local police are using Facebook's check-in feature to monitor traffic in and out of the massive protest camp.
"Local law enforcement are trying to use Facebook to track the peaceful protesters, so the massive spike in check-ins throws them off," The Check in at Standing Rock Facebook page reads.
"The viral check-ins are raising the profile of the protest because it's received almost no mainstream media coverage."
But the Morton County Sherriff's Department vigorously denied these claims.
"The Morton County Sheriff's Department is not and does not follow Facebook check-ins for the protest camp or any location. This claim/rumour is absolutely false," said the department in a Facebook post.
However the Sacred Stone Camp, one of the primary organisers, claims "there is no doubt law enforcement comb social media for incriminating material and monitor communications".
While they say they are not responsible for the viral campaign, the Sacred Stone Camp said in a statement: "We support the tactic, and think it is a great way to express solidarity. The copy and paste technique has created a unique way of generating numbers of support - it's more impactful to see thousands of our friends take the time to create a unique status update."
The Facebook loophole, which allows users to check-in anywhere in the world even if they aren't physically there at the time, has now become an essential tool for the pipeline protest itself - a pretty great example of using social media to lend a hand to activism.
The reservation has a population of less than 10,000, Time reports. And, while thousands of activists have descended on the site in recent months, the total number of protesters on the ground is far below 900,000.
The Standing Rock Sioux tribe has opposed the Dakota Access Pipeline since first learning about plans for the project in 2014. But it has only been in recent months that the issue has gained national attention, partly thanks to prominent figures such as actor Mark Ruffalo and political activist Jesse Jackson, as well as actress Shailene Woodley, who was arrested at the site last month.
Last week, the Morton County Sheriff's Department began an effort to physically remove protesters from the location, using armoured vehicles to push people back from the construction site, arresting around 140 of them. This subsequently caused a huge surge in the number of protesters flocking to the site to join in the demonstrations.
Meanwhile, a crowdsourcing goal of just $5000 (NZ$6900), enough to help a few dozen people camping in North Dakota to protest the nearby construction of the four-state Dakota Access oil pipeline, has since topped a staggering $1 million (NZ$1.39m).
The fund is among several cash streams that have provided at least $3m (NZ$4.16m) to help with legal costs, food and other supplies to those opposing the pipeline. It may also give protesters the ability to prolong their months-long encampments that have attracted thousands of supporters, as the Standing Rock Sioux Tribe pursues the fight in court.
"The Standing Rock Sioux are not going away; instead, they have vowed to continue their protest over the winter," a recent post on the official Facebook page reads.