Digital Realty owns and operates over 200 data centers worldwide. It has more than 30 million rentable square feet and over 2,300 customers. Digital's offerings range from retail colocation, where an enterprise may rent a single cabinet and rely on Digital to provide all the accommodations, to "cold shells," where hyperscale cloud service providers can simply rent much, or all, of a barren, power-connected building. In recent years, Digital Realty has de-emphasized cold shells and now primarily provides higher-level service to tenants, which outsource their related IT needs to Digital. Digital Realty has also moved more into the colocation business, increasingly serving enterprises with smaller space and power needs. Digital Realty operates as a real estate investment trust, or REIT.