For the record, there is only one Aloe vera species. Many of the plants on the market (and the internet) which are labeled "Aloe vera" are not Aloe vera at all. To give you an idea of the big picture, there are maybe 500 total aloe species, of which A. vera is one (and my avatar, for example, is another). Many people assume that their random aloe is Aloe vera without considering the hundreds of other options.
I have actually had to stop people harvesting leaves in the public garden here because there are maybe 30 different aloes in there and only two or three of them would be considered medicinal. There are actually poisonous aloes out there (not many, and very uncommon) so it's good to figure out some kind of ID before cutting leaves from a random aloe.
