Amazon just increased prices on a service you've probably never heard of, and some researchers are really upset

Amazon just raised the costs of using Mechanical Turk - its platform to let users crowd source "human intelligence tasks" to people all around the world - and researchers aren't happy, the Wall Street Journal reports. 

If you think of Amazon purely as an e-commerce site, you've probably never heard of the service. But it's been around for nearly ten years and is used by people all around the world.

Mechanical Turk essentially gives users access to an on-demand workforce, while simultaneously giving people who want to make a little extra money a way to find quick-and-easy online labor.

Here are some examples from the site of jobs people can complete: You can get paid $0.04 per picture to find images of specified real estate agents, or $0.02 to copy text from a picture of a business card.

On Monday, Amazon announced that it was doubling the commission it takes from 10% of the total paid to 20%, and adding an additional 20% commission when requesters need more than 10 people. 

It didn't take long for a backlash to erupt on social media, in particular through the hashtag "mturkgate."

One of the groups particularly affected are academic researchers. 

Because Mechanical Turk was an easy way to poll large groups, researchers often used it to complete studies.  

As Princeton University's research center succinctly puts it, "It's a relatively low cost way to engage a diverse set of respondents in a short period of time."

But the new pricing model means that researchers will either have to pay more or - equally troublingly - pay the people completely their surveys less to stay within the same budgets. 

Because the commission increase is so dramatic, people have started to call for the introduction of an academic tier or pricing.

In a Facebook group for marketing academics who use Mechanical Turk, one user wrote he spoke on the phone with someone from Amazon. 

Although the company declined to comment on this post, it did send Business Insider the following statement:

These changes will help allow Amazon to continue growing the Amazon Mechanical Turk marketplace and innovating on behalf of our customers. We think these changes will help us better serve our community of Requesters and Workers.

Disclosure: Jeff Bezos is an investor in Business Insider through his personal investment company Bezos Expeditions.