File-sharing site FileSonic has announced that it is has disabled "all sharing functionality", and that its service can "only be used to upload and retrieve files you have uploaded personally".
The company's Facebook page has also disappeared. According to users on Reddit, it is believed that many accounts and files were deleted today.
It is thought that this measure has been put in place in response to the wider crackdown on file-sharing sites by U.S. authorities.
U.S. and New Zealand authorities shut down one of the Web's most popular online properties, Megaupload, last week. Its founders and three other employees were arrested and detained. They are awaiting extradition to the United States to face copyright infringement and money laundering charges.
Within a few hours of the news breaking, hacktivist collective Anonymous retaliated by attacking the websites of the RIAA, the MPAA, the FBI, and the U.S. Justice Department by way of denial-of-service attacks.
Late last week, Uploaded.to blocked all U.S. visitors from accessing its site as part of efforts to distance itself from U.S. jurisdiction.
Another popular file-sharing service, RapidShare, said in an interview with Ars Technica that it was "not concerned", adding that, "file hosting itself is a legitimate business". The file-sharing giant is based in Switzerland, and is "set up in a much more transparent way".
RapidShare and FileSonic comply with DMCA requests, and both have dedicated staff to remove illegally uploaded content.
FileSonic did not respond to comments at the time of publication.