Well, the short answer is: NO.
You cannot share a link for your app to people outside your organization - that breaches your agreement with Apple. However, I know that some companies do that kind of "beta invitations". Here's my old answer on "How do we publish our ios application for only our customers via our servers?", take a look.
So you think you're stuck with 50 promo codes per version and 100 devices for internal testing? Thankfully, NO! :) This article will shed some more light on how one company distributed over 3000 copies legally. It's worth a read IMO.
EDIT: if you're looking for a formal NO, search for iOS Developer Enterprise Program, where it's stated explicitly that if you share apps outside your organization you account may be suspended/closed.