I've written briefly here about big data and commercial real estate (CRE). Earlier this month at our annual conference, I addressed the topic more broadly. An online search engine scours billions of web documents for their relevance. As a matter of big data, one could think of this as "long data." In CRE, big data will not be long. Rather, it will be wide: many, many attributes observed for a limited number of properties. In other words, only a proprietary dataset can fulfill big data's promise for CRE.