As stated on the ISTE website:

Your year-round connection to ISTE members and decision-makers begins with booking an exhibit space in our annual exhibition. It continues in myriad ways through advertising, ISTE 100 membership, our social networks, and other special ISTE professional development initiatives like webinars and virtual events. By connecting as a primary ISTE exhibitor, your company and organization gets in at the ground with nowhere to go... but UP!