Are there limits to how many users can view or download the same ebook at the same time?

Most NC LIVE ebooks have no holds and no simultaneous user limits, but a few collections do have limitations.

Collection Usage limits
ABC-CLIO E-book Collection Unlimited users
Credo Reference - Complete Core Unlimited users
Ebook Central Academic and Public Library Complete Unlimited users
Ebook Central Permanent Collection (formerly MyiLibrary) Maximum of three users per title for viewing and downloading
eBooks on EBSCOhost One user per copy; many titles have multiple copies (usage limits = concurrent user level)
Gale Virtual Reference Library Unlimited users
HomeGrown Ebooks Collection Unlimited users
Open Library One user at a time for every title
RBdigital eBooks Unlimited users for classic titles; One user per copy; many titles have multiple copies
SIRS Discoverer Unlimited users
Testing & Education Reference Center Unlimited users