Not usually. E-book readers are those that know about e-books and read them often. Romance and Erotica currently hold a large portion of the market share, which means that most of the readers I'll get with this first e-book will be from that market (so it's a good thing Samhain does a lot of romance, eh?) but there are fans of other genres that buy, sure.
Samhain books are sold at My Bookstore and More, then at Fictionwise, I think, a little while after the book comes out. And I see that at least a few of the titles are available in the Amazon Kindle store.
Print books - well, they have the store placement, so you're getting the people who wander into bookstores, or read reviews.
I don't think they're the same readership. I personally think I'll reach a whole new audience with the e-book, since this is my first big e-book release. Hopefully that'll sell my backlist.