This has bitten me in the rear a number of times: I download a free/open source/whatever source component, plug it in my project and… Visual Studio complains the assembly is not strongly signed. We always sign our assemblies, so compiling with unsigned ones becomes a problem. We’re lucky if the 3rd party component comes with source code so we can throw in a .snk file and recompile it.

Conventional wisdom says a signature is need only if the assembly goes into GAC. This is correct, but signatures are also a way of disciplined versioning. I understand it’s a point of contention to some people, but I side with proponents of strong signing (Jeffrey Richter, for example).

I’ve been guilty of not following this rule myself, but I became converted once I heard Jeffrey Richter speak on this subject.