An IX (Internet Exchange) allows networks to interconnect on an open-access ethernet fabric -- providing low-latency, high-bandwidth, cost-effectively, in a locale.
Networks can exchange traffic faster and better. ISPs, transit providers, DNS services, and content networks will congregate -- it is sensible to interconnect locally.
Traffic exchange is facilitated by BGP (Border Gateway Protocol). Networks must have an AS (Autonomous System) number to announce their routes to each other.
Participation in YYCIX is free. Connecting into the locations is subject to agreements with the facilities. The sum of benefits builds as more peers join.