If you've ever wondered how sites like Tumblr get away with displaying copyrighted images, you're not alone. Now one of the Internet's biggest players — the porn industry — is eyeing Tumblr for copyright infringement.

Adult publisher Perfect 10 is suing Tumblr for $5 million for "rampant and unremedied uploading, display and distribution of Perfect 10's copyrighted photographs."

In the complaint, Perfect 10 states that Tumblr's reblogging platform allows "subscribers to copy and distribute infringing content at the touch of a button."

The complaint also states Perfect 10 sent former Tumblr president John Maloney six Digital Millennium Copyright Act (DMCA) email notices to take down the more than 200 images, but as of the date of the complaint filing, Tumblr had removed "at most only a handful."

This is a direct attack against Tumblr's biggest defense, "safe harbor laws," which states that users — not hosts such as Tumblr — are responsible for copyright violations.

According to the porn company, "Tumblr should be held liable for its failure to abide by its obligations under the DMCA and for willfully ignoring the widespread and uncontrolled copyright infringement pervading its website."

SEE ALSO: How the Web Has Changed Our Perception of Copyright Law

Especially with the controversy regarding the Stop Online Piracy Act (SOPA), some have argued that it was only a matter of time for Tumblr to be held liable for copyright violations.

Tumblr is not the only Internet site Perfect 10 has blacklisted. In the past, the porn company has also sued several companies for allegedly misusing its images, including Google, Microsoft and Amazon.

If Perfect 10 wins this lawsuit against Tumblr, it could have a ripple effect with other sites. With its "re-pinning," Pinterest, for example, might be susceptible to a copyright lawsuit.

Do you think Tumblr is guilty of copyright infringement? Should users or hosts be responsible for what's on the internet? Sound off in the comments.