Update README.md

Author: mathewc

README.md

@@ -12,6 +12,8 @@ This repo contains libraries that enable a **light-weight scripting model** for
 
 These libraries are the runtime used by [Azure Functions](https://azure.microsoft.com/en-us/services/functions/). The runtime builds upon the tried and true [Azure WebJobs SDK](https://github.com/Azure/azure-webjobs-sdk) - this library just layers on top to allow you to "**script the WebJobs SDK**". So you get the full benefits and the power of the WebJobs SDK, including the [WebJobs Dashboard](http://azure.microsoft.com/en-us/documentation/videos/azure-webjobs-dashboard-site-extension/). 
 
+**An important note on language support levels** - while many languages are supported, their level of support differs in important ways, making some languages more suitable than others for certain workloads. The **first class** languages are C#, F# and Javascript/Node.js. Functions written in these languages are run **in process** and are suitable for any workload. The remaining languages are considered **experimental**. Functions written in these languages are scripts that are run **out of process**. While there are many scenarios where this is acceptable, it won't be acceptable for high load scenarios where the overhead of a new process for each invocation won't scale. That said, there are many traditional WebJobs scenenarios where this limitation is acceptable.
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 As an example, here's a simple Node.js function that receives a queue message and writes that message to Azure Blob storage:
 
 ```javascript