How did the poem “Mary Had a Little Lamb” become so famous?

“Mary Had a Little Lamb” was written in 1830 by Sarah Hale, the edi-
tor of Godey’s Ladies Magazine. She was inspired after watching young
Mary Tyler’s pet lamb follow the girl to school, which, of course, was
against the rules. The poem became immortal more than fifty years
later when Thomas Edison used it as the first words ever spoken and
then recorded on his new invention, the phonograph.