“MacArthur Park” (not “MacArthur’s”, as [Richard] Harris insisted on singing) is a dreamy, musically complex, highly impressionistic song about Webb’s break-up with his girlfriend. The lyrics contain some unforgettable metaphors for loneliness and shattered dreams, including a cake left out in the rain — an image that a lot of people seem to find either hilarious or bewildering. In 1992, columnist Dave Barry asked his readers to vote on the worst song of all time and “MacArthur Park” won. I beg to differ, but, whatever.
– Joyce Millman, Tales from the bargain bin: “MacArthur Park” edition
Nice piece, though my own 1968 bargain bin classic remains “Classical Gas,” which has never not sounded scary to me (and though I like Harris’s song, I consider Donna Summer’s version definitive — maybe she’s the Pet Shop Boys to his Village People?). I’m racking my brain, though, trying to remember the last time contemporary pop radio even admitted a song as over-the-top/left-field as this. Early Meat Loaf, maybe?
RockCritics.com 
Oh, wow, I remember watching Mason Williams playing this for the first time on the Smothers Brothers show. Between this, “MacArthur Park” and “Hey Jude”, 1968 was the year AM radio grew up. The radio landscape and the way music is consumed in general is so radically different now, I’m not sure your question can be answered.
No, I agree, it’s comparing apples and oranges, though maybe my point is that in 1968 it was apples and oranges (and grapes and strawberries), whereas today it’s, I don’t know, raisins? (Which btw, isn’t entirely a comment on the ‘quality’ of pop music, but is most definitely a comment on whatever passes for pop radio),