I've heard some talk about these. My question is "what vehicle classification" does it fall under? I always hear the term "glorified scooter" brought up with these.., and their website appears to use the term as well (if you can get on the website too because their server just plain sucks and is very slow).

Every state has different laws that govern these types of vehicles. Clearly the motor will have to be 50cc's and above if this is a 2 person unit.., and taking it's size into consideration. If it's a scooter with a 50cc motor or above it'll fall under the Motorcycle laws. Many states have laws that cut off at 50cc's and if under 50cc's most states apply "bicycle law" to them.

Probably would be required to wear a helmet in most states with this as well. Again.., depending on how the vehicle is classified by your states DOT.