Qualified convention and trade show activities conducted by organizations exempt under section 501(c)(5) or 501(c)(6) are not unrelated trade or business if:
The activities are designed to attract persons to a show for the purpose of displaying or stimulating interest in and demand for the industry's products, or to educate persons engaged in the industry about new products or matters affecting the industry; and
The event is sponsored by a section 501(c)(5) or 501(c)(6) organization that regularly conducts such shows as one of its substantial exempt purposes.
If an activity is not unrelated or trade or business, it is also an exempt activity of the organization that conducts it.
Shows that are designed merely to bring buyers and sellers together, not in conjunction with an annual meeting or to stimulate demand for products of the industry as a whole, are not within this exception.
Revenue Ruling 2004-112 : Whether Internet activities conducted by an exempt trade association are within the specific exception for qualified convention and trade show activity under Internal Revenue Code section