The image above was taken from the "Product Details" section of the Amazon listing for Grand Theft Auto IV. As you can see, Amazon has begun tagging video games with a "recommended age", based on their content. As you can also see, the age range tops out at 20. The company provides a similar service for the items listed in their Toys and Games department.
In other words, Amazon believes that video games are toys and that people over the age of 20 shouldn't be interested in them.
Of course, in still other words, the new "recommended age" field was likely added to video game listings as a service for parents who may not be aware of the adult content some games posess. And rather than creating a new field in their product creation database, Amazon likely reused the one from the Toys and Games department.
The problem with that is that video games already have a well recognized way to match a game's content with an appropriate age range: the ESRB ratings.
http://www.gamingtarget.com/article.php?artid=10098
