Facebook's "Like" feature must have free-speech protection, a US court has been told.

Controversy ... Facebook is being sued for its 'like' button. Photo: Mashable

This post was originally published on Mashable.

You can bet Facebook doesn't like this.

The social network is currently being sued for its use of the 'like' button, a feature that was patented by Dutch programmer Joannes Jozef Everardus van Der Meer in 1998, five years before Facebook's launch.

The patents were granted as part of the functionality of Surfbook, a social diary created by Van Der Meer that allowed users to "like" each other's content.

Van Der Meer has since passed away, but the patent holder – Rembrandt Social Media – is seeking legal action against Facebook, as well as the company AddThis, for using the patents without permission.

"We believe Rembrandt's patents represent an important foundation of social media as we know it, and we expect a judge and jury to reach the same conclusion based on the evidence," attorney Tom Melsheimer, counsel for Rembrandt, said in a statement.

The lawsuit was filed in Virginia, US, on February 5.

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