Wednesday's Mother Goose post (and the birthday of a good friend) put Pollyanna/Polly on my mind. And you know, once Polly's in your mind, she tends to stay a nice long while.
The song's a cautionary tale, however —
Polly wouldn't listen to her mama
Polly wouldn't listen to her papa
she tried to make the swinging city scene
and now there's not a place that Polly hasn't been
Polly, pretty pretty Pollyanna
pretty pretty Pollyanna
pretty Polly Garter
oh I think that pretty Polly should have stayed at home
As I said in the previous post, Polly's a nickname for Mary (though I have heard of it used as a nickname for Margaret as well) and Pollyanna is a name-smush made famous by a novel — 1913's Pollyanna by Eleanor H. Porter — and a 1960 film, based on the book.
Polly fell off the charts (it had been a steady 200-400 range presence since the 1880s) in the 1970s rather abruptly. In '74 it was at #692 — by '75 it had fallen to #866, and in 1976 it did not appear in the top 1,000. Curiously, it did appear in 1977, at #798. Since then it has not ranked.
In 2010, there were 35 baby girls born in the US named Polly, and no more than 5 named Pollyanna (Pollyanna has not appeared in the top 1,000 for at least 132 years) — if you're looking for a very uncommon name that has the charm and appeal of an historic nickname, Polly's a (pretty pretty) solid choice.