
I read that they were used for herding reindeer..
ETA - "A herding dog in northern Russia, the Samoyed acquired the name after the nomadic tribe it served. They were also used to guard the reindeer that they herded. The Sami worked closely with the tribe and shared their tents, so has a great love of family life. On occasion they were used to pull sleds or boats, but this work was usually reserved for the reindeer."
from
http://www.petplanet.co.uk/petplanet/breeds/Samoyed.htm