This white paper talks about the differences between Shared add-ins and VSTO
add-ins:
Migrating a Shared Add-in to a Visual Studio Tools for Office Add-In
http://msdn2.microsoft.com/en-us/library/aa663367.aspx

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Harry Miller
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>I am struggling with the distinction between a VSTO Excel AddIn and a
> Shared AddIn. It seems that with VSTO Excel AddIn that I cannot
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> Thanks in advance for any direction you can give me.
> Darryl