I looked it up and turns out he was right: on the maps of the Russian domain - yandex.ru - Crimea is shown as a part of Russia; while on the Ukrainian - yandex.ua - it is still a part of Ukraine.
Ukraine according to maps.yandex.RU.
Ukraine according to maps.yandex.UA.
Then, I decided to check out Google Maps, since we usually expect a little more neutrality -- perhaps -- from global companies. Interestingly enough, the picture seemed as confusing there.
On maps.google.RU, Crimea is most certainly within the Russian territory (note the solid line separating the peninsula from mainland Ukraine).
On maps.google.UA, however, there seems to be no border at all between Ukraine and Russia in the South (i.e. nor a line between Crimea and mainland Ukraine, neither between Crimea's East and Russia -- on the Kerch side). Confusing, eh?
On the generic maps.google.com, the picture was perhaps most "politically correct", with a dotted line separating the peninsula from the rest of the country, thus indicating a disputed territory.
Of course, it's no fun being an international tech company stuck in between those nasty political disputes. However, does market/audience segmentation really work in the Internet age? If anything, it is a cause for further frustration and disappointment for the people on the ground. Plus, how long does Google need to decide where Ukraine's Southern border is..?