..NET still has MTS/COM+, which it now refers to as Enterprise Services
although it has taken a back seat to other options that are available
natively in .NET to simply "host a dll". If you don't need to use services
specific to enterprise services such as distributed transactions or queued
components you should simply use one of the other native implementations
that .Net offers for exposing/hosting components/classes/data on a server
such as .NET remoting and Web Classes. Each of these options are catered
towards specific needs & business requirements. Enterprise Services adds
unneeded overhead and complexity for simply hosting components.
Regards,
Josh Carlisle