Oddly-shaped House on Seurasaari

I bet the first story was finished out when the builders were comparatively young and poor, and the second story added later as money and time allowed. Although it's odd to cantilever at least three sides of a home, it's not impossible. From what I know of house design, having floors above empty space tends rather to cool the space due to airflow under the floor bearing away heat.

But it keeps the snow from piling up against the walls and windows. The roof structure is typical of areas with heavy winter snow accumulation.

I don't know about Finland, but in some jurisdictions, property taxes are based on frontage, rather than total square footage. If you make the upper floors larger than the ground floor, you can pay less tax for the same amount of floor space.

So you get lots of buildings with overhanging upper storeys.

It never looked as a typical Finnish house to me, but I haven't bothered my head with it. But snow fall isn't that heavy here.

I had to check the web pages of the Seurasaari Foundation. The Finnish section explains that the architect of the island, Frithiof Mieritz (1863 - 1916), designed that house in a Norwegian style he had learned during a trip to Holmenkollen. Also other buildings of the public park are evolutions of stabbur.
http://commons.wikimedia.org/wiki/Category:Stabbur

Note that those buildings are not connected with the outdoor museum that displays old Finnish folk architecture (skansen).

I did see many buildings in Bulgaria that are similar, though not identical. The style there is "Bulgarian National Revival"--as it was explained to us, it was a means of keeping streets passable while maximizing floor space (upstairs, at least). Once it is a fashion, even a house not directly on the street could share those features.

oh no! what is the world coming to if digital cuttlefish has stopped writing in rhyme?

The house does look very traditionally Norwegian. A pretty simple house that is well proportioned and an interesting design. The original colors would have likely been much more vivid.

Dunno about the house design in itself, but that vine or shrub climbing all over the wall has to be doing some serious damage to the paint and tightness of the exterior siding, not to mention making the interior dark and gloomy (unless there are no windows on the any part of the entrance side, an even weirder design decision).