In Soviet times apartments were assigned by state authorities in accordance with the standards of living space designed for one individual, regardless of marital status so often 2-3 or even 4 persons ended up living in a room really meant for one person.
That’s true. Communal flats is a social experiment organized by communists. There were huge number of kommunalka with appalling living conditions in the former USSR, and lots of them still exist these days. According to Wikipedia, about 660,000 people lived in such flats in St. Petersburg in 2011. Lenin personally masterminded the creation of such accommodations in one of his works describing in detail the process of taking over the housings of richer people. In 20th and 30th former owners were evicted from the remaining rooms and devoid of civil rights.

http://ru.wikipedia.org/wiki/Коммунальная_квартира