I've never read the series, actually, though I think I would like to sometime. I have watched some of the movies, though. I don't think that "Katy" from "What Katy Did" is supposed to be the same "Katy" as in the "Anne of Green Gables" Series.
What a coincidence, though! Just a few days ago, I was thinking that I would like to read the "What Katy Did" series. Seeing as I have had it for quite awhile, but never read it! And it does look interesting!