Despite the song's catchiness, it was passed over as the lead single from the album; the track "So Long" was chosen instead. "So Long" was chosen primarily because it had the same uptempo beat as their 1974 hit single, "Waterloo."
The descending chords and ominous synthesizer melody line of the introduction set the tone for Faltskog's vocals, sounding almost as if she were breaking down in tears."SOS" was the song that put the group back on the worldwide charts. It was their UK comeback, peaking at No.6, and a U.S. Top 20 hit. It continued the craze of "Abba-mania" in Australia, where it, along with other singles, "I Do, I Do, I Do, I Do, I Do" and "Mamma Mia," occupied the top spot for record weeks at the time. "SOS" also topped the charts in New Zealand, Mexico, South Africa, Belgium and West Germany, and reached the Top Five in Italy, Austria, the Netherlands, Norway, Zimbabwe (then Rhodesia), Switzerland and Ireland. The track was also the group's first charting single in Canada, peaking at No.9. From this point on, ABBA were guaranteed recognition as a force in 1970s popular music and were no longer regarded as Eurovision one-hit wonders."SOS" has a number of musical fans: John Lennon and Pete Townshend had both declared that it was one of their favourite pop songs. Pretty credible endorsement if you ask me. ABBA Rocks and I Love them with all my heart. Hope you do also. Click on my username 7ABBA7 or subscribe for access to all my ABBA vids. 973 million coming. :P Peace ABBA Fans! :)