So, you have this song. It's pretty cool, but the fadeout is kind of long. What do you do? Continue the fadeout into the beginning of the next song on the album, and copy-paste the intro of the second song over the fadeout. Live songs and medleys don't count. Concept Albums most definitely count. This refers only to when a song's fadeout spills into the beginning of the next one — sound effects, abrupt switches without gaps and other transitions don't count. Albums that do this all the way through are known as "gapless albums".