Well print has to have an ISBN. CS isn't going to do you a version without one afaik.
If it's a different file type (mobi, epub, pdf) or a same format with different DRM (Adobe epub vs B&N DRM epub) it is supposed to have a different ISBN. None of which will make any difference to anyone but Bowker's stockholders. Again. IMHO.
As I've explained before, both here and in other conversations we've both participated in at AW, publishers get a huge amount of very useful data from their use of ISBNs. If it were only Bowker's stockholders who were affected by the use of multiple ISBNs, trade publishers wouldn't do it. Why incur an unnecessary expense?
In terms of sales data, in terms of KDP, NookPress, etc. you have up to the day sales information. ARe even breaks down what format the customer buys from. My understanding is that most trade published authors don't get information nearly as detailed or timely, not sure if the publisher's do or would even care.
The good, bigger, publishers subscribe to
Nielsen BookData, which allows them to look up any ISBNs they want to and find out the current levels of sales--even those for books they don't publish. So yes, they have the same levels of sales data available via KDP etc, and from what I've gathered, they get more detail and more history than KDP etc provide.
Publishers also have their own sales records (or those of their distributors, of course) which they can compare to the sales figures Nielsen reports to get a good idea of what's happening out there in bookselling-land.
Writers who are published by trade publishers tend not to have access to such information (although we are all able to subscribe to Nielsen if we can afford the subscriptions): they receive royalty statements and payments as frequently as their contracts stipulate, which is usually twice a year--but as most of the better literary agents also subscribe to Nielsen, they do get more frequent updates if they want. For example, they'll be able to find out how well their books do in pre-publication, and on publication day, and so on.
It is kind of nitpicky. When you first get started, it's sort of interesting (and thrilling) to know you sold X copies of ebook of Title X in Italy on Y date, but after a while it's like "how much are they depositing in my bank account on what date?"
With all due respect to all the self-publishers I know who work really hard, it must also be discouraging to see that after all your hard work you've only sold four books in a week, though. At least a royalty statement once every six months usually presents a more robust number, even if the daily figures are no better!
My guess would be the cases of the discrimination against CS are overhyped anecdotes rather than a pervasive bias amongst booksellers, but that's truly severe guesswork
I'm sure it's real. They would have ordered one book and you would have made one dollar on a ten dollar retail price, half what you made on a $2.99 ebook. Big whoop.
Katie, why are you "sure it's real"? How many writers do you know who have had bookshops refuse to stock their books based solely on the fact that it sported a CS ISBN, rather than a Nielsen one?
If their books were refused with that reason, are you sure it's a reason and not an excuse, made because the bookseller thought the book concerned was of a poor standard but didn't want to hurt the writers' feelings?
And if that reason were given, then it could be a real difficulty, rather than discrimination against CS, caused in great part by reasons I already outlined earlier in this post.
It's true that not having a standard ISBN can cause problems for bookshops who want to stock the books concerned: but their reluctance to do so is not usually discrimination or a sneery attitude to self-publishing. The issues are the complexities of doing business with publishers which are outside the usual loop, and a lack of quality in most of the books offered under such conditions.
The reality of print is "they're just not that into you." Most people I know are more concerned about audiobooks than print.
Most people I know are more concerned about good books. Some prefer e-books, some prefer print, and some prefer audio books. It's the content that's important, not the container you put it in. Although if you want to maximise your sales, it's wise to put it into as many containers as you can, and not dismiss any of them as dull or unimportant.
Welcome ljnDawson. Cathy, agreeded on the difference. I think a page directed to assist self-published authors takes some of the scarey out of it. I think some don't do it because it seemed like it was just for publishing companies not authors as themselves, if I'm saying that right. 
