According to the site:
"A song-poem, it turns out, is nothing more nor less than a set of lyrics to a single song. Song-poem music is that which results when these lyrics, submitted by readers of ads such as the one above, are set to music by studio pros, who churn out finished recordings on an assembly-line basis, sometimes pumping out an amazing quota of 12 songs per hour! Belying their inherently prostituted origins, these finished song-poem recordings are sometimes quite remarkable, either by being so inept in all directions as to defy belief, or by being weirder than the weirdest thing you've ever heard. Sometimes they are both at the same time."
I haven't yet succeeded in sampling the musical wares available at this site, but I'm assured they're well worth the time. Especially Little Betsy and Her Goat. Such amazing cultural riches online!