I can't think on any reason to add SNK signing (e.g. add a Strong Name) to Silverlight (including Windows Phone) output assemblies!
This gives a lot of versioning problems to other library developers who use Json.net, as you can see here on RestSharp:
Adding Strong Names is great ifwe want to add the assemblies to GAC, but that for full .NET Framework only, not for Silverlight or Windows Phone!
In the full .NET we can always use Assembly Redirection or Publisher Policies to bypass this issue, but once again, this can't be achieved in Silverlight or Windows Phone!
So PLEASE don't add a strong name to silverlight and windows phone output assemblies!!!!
Thank you and best regards,