Tuomas Holopainen, the composer, has stated that the title is Latin for "nobody" and the song is based on his occasional feelings of being lost, longing for the past and feeling nameless. This contradicts speculations that the song simply borrows on a Nemo character of an earlier work, such as J. Verne’s Captain Nemo, Homer’s Ulysses alias Nemo, C. Dickens’ Captain Hawdon alias Nemo, W. McCay’s Little Nemo, or the Disney Studio’s film Finding Nemo. Asked about that T. Holopainen responded:
Not the fish! I cannot believe how everyone seems to be convinced it’s that. Nemo, which is Latin for "nobody," has nothing to do with the Disney film. It revolves around the feelings I have from time to time. I feel nameless and do not know who I am or where I will go. I only know my past and I long to be back there. The song is about being lost, not knowing where to go or what to do, yet desperate for everything in life. That’s not always me, but when I wrote Nemo, that’s the way I felt. Now I feel better. (Translated from the German)
Once topped the album charts in Finland and Hungary. In the UK it could only chart at #87 after a chart entry of #101 the week before, but spent over 20 weeks on the top 200 plus a few re-entries. However it has been in the top 10 of the UK Rock Chart as recently as May 2008, highlighting the recent acclaim the band has had in the United Kingdom.
Nemo was certified with Gold Disc in Finland one week after release, with more than 5,000 sold copies, and got Platinum disc after two weeks, with more than 10,000 sold copies.