Exclusivity is a word with two serious commercial lives. In luxury and membership it means scarcity and access. In law and commerce it means a binding arrangement: exclusive distribution, exclusive licensing, exclusive territory.
Both readings support a business. A members’ club, a private marketplace, a luxury platform, or an invitation-only network on one side. A contracts and licensing resource, a distribution rights marketplace, or a legal practice on the other.
What makes the word strong is that it names a mechanism rather than a product. Mechanisms outlast products. Whatever the specific business, the underlying idea of restricted access is permanent and permanently valuable.
The .net suits a platform or network reading particularly well, and for a members-only operation the extension costs nothing, because people arrive by invitation rather than by typing a guess into a browser.
One long word, spelled exactly one way, with no plural and no regional variant.
The name is available. Enquiries welcome.