app.config

This is application specific and should be considered a "read-only" file
This contains settings specific to the application

This appears as app.config in your IDE and is then automatically renamed when the project is built.
Application settings allow you to store and retrieve settings and other information dynamically

<configSections> 
</configSections> 

<system.diagnostics> 
</system.diagnostics> 

<system.serviceModel> 
</system.serviceModel> 

<applicationSettings> 
</applicationSettings> 

<userSettings> 
</userSettings>

Exact FileName

The name of this file depends on the type of application.

Executables / Addins - file name is "nameofapplication".config

Accessing from Code

You can access these settings using

Properties.Settings.Default

If you want to persist the changes call the Save method.

Properties.Settings.Default.Save

My.Settings

Web Services

Property	Description
MaxBufferSize	The maximum size of the buffer to use
	For buffered messages this value is the same as MaxReceivedMessageSize
	For streamed messages this value is the maximum size of the SOAP headers which must be read in buffered mode.
MaxReceivedMessageSize	Must match the "MaxBufferSize"
MaxStringContentLength	The maximum string length returned by the reader
	When deserializing the message this property is used to block messages over a certain size.