Comments by David R. Green (Top 1 by date)

I disagree. Class Library DLL's are a terrible thing and should never be used outside of what the OS itself includes.
Most developers throw their DLLs into the Windows System folder during install, then never remove them during uninstall; they break their own DLLs with versioning issues; and generally cause all manner of end-user and IT problems.
It is just as easy (or easier) to use Add As Link to existing common source libraries to integrate them into the single assembly/executable.
Microsoft should include a metatag that hides classes from Intellisense, that would be the superior route.