The “Worst Roller Coaster Accident in Sydney” message on Facebook is a scam which has been launched by Facebook scammers. The scammers behind the “Worst Roller Coaster Accident in Sydney” Facebook scam try to lure unaware users to a malicious website which forces the victims to like and share the specific website.
Once the victims have shared the malicious page, they will be redirected to another website which will try to lure them to a online revenue generator which has been hosted by the scammers.
This allows the scammers to earn money from the victims. It is possible that the scammers will decide to upload malicious files to the scam website. Allowing them to hack and control any computer which installs and executes the malicious files.