This is the fanlisting for the relationship between Alex P. Keaton and Ellen Reed (played by Michael J. Fox and Tracy Pollan) on the 80s sitcom Family Ties.
The site is named for a song by Billy Vera & The Beaters, the song that Alex and Ellen first danced to, making it "their song."
What is a fanlisting? According to TheFanlistings.org, "a fanlisting is a place for all fans of a particular show, movie, actor, actress, singer, etc. to come together and build the biggest listing of people from all around the world who are fans of that subject."
So, if you're a fan of their relationship, join the fanlisting!