It is sung from the point of view of a young man, about a woman called Ieva (dialectal for the name Eva or Eeva in standard Finnish) who sneaks out and dances the polka with him all night.
Polka was introduced into Northern Europe during the late 19th century, which implies that the tune, as it is known today, originates from this era.
The Loituma version of the song acquired great international popularity as part of an Internet phenomenon in the spring of 2006, when the Loituma Girl (also known as Leekspin), a looped animation of anime character Orihime Inoue from the Bleach series twirling either a spring onion (in the Japanese original) or a leek (in the English dub), set to a scat singing section of the song, was posted on Russian LiveJournal.
The most popular Vocaloid cover belonged to Japanese artist Otomania, who in 2007 made Hatsune Miku sing it with the nonsensical lyrics by Loituma.
Its popularity resulted in its use by the Vocaloid rhythm game series Hatsune Miku: Project DIVA, mainly as tutorial music.