Why do some resources in Azure say (classic)?

Q. I notice in the new Azure portal may types of resources have (classic) in their name, what does this mean?

A. Many services were initially built on the Azure Platform as a Service (PaaS) base which used the Azure Service Manager (ASM). Recently the new Azure Resource Manager (ARM) has been released which provides a completely new of capabilities and removes many of the limitations of ASM. When you see a resource with (classic) in its title it means its managed by ASM instead of the new ARM. Where possible start to leverage the non-classic resources however at time of writing there are some limitations for certain ARM based services and you cannot mix ARM and ASM resources, for example an ARM VM cannot use ASM storage or networks.