True cloud services all use some mode of multitenancy — the ability for multiple customers (tenants) to share the same applications and/or compute resources. It is through multitenant architectures that cloud services achieve high cost efficiencies and can deliver low costs. Multitenant architectures must balance these cost benefits with the need for individual tenants to secure their data and applications. Forrester finds that few application development and delivery (AD&D) pros understand how multitenant architectures balance sharing with security, and many have other concerns as well. This research will clarify the picture and guide you to make good decisions about cloud services.