scam is a widely used term. scam can be many things, such as a website that offers you software that is free of charge, but secretly charges a subscription fee via a scam site.
Scam sites at MG already existed. Websites with promises like "xy Gold" and much more, the only thing that was gone was the account. But also websites used monster games to advertise their subscription traps and sent spam in the game with e.g. "Hasimausi". A website that supposedly moved women to undress by clicking a link. The only thing that moved there were the reminders to the people who had subscribed there.
Therefore you should always pay attention if you click on links or register on pages or enter your data coming through a link.
More about rip-offs and discussions about it can be found at Arcade Worlds Forum. (german)
Information can also be found in the MG Blog (german)