Question: What EXACLTY (what registry keys it writes) does the ATL::CComModule::RegisterServer(TRUE) call do?

Answer: 
For each class that uses the [`OBJECT_ENTRY_AUTO`](http://msdn.microsoft.com/en-us/library/exx3wywe.aspx) macro, it will run the corresponding registry script resource (.rgs file) listed in your resource file, as identified by the [`DECLARE_REGISTRY_RESOURCEID`](http://msdn.microsoft.com/en-us/library/w0ey2be3.aspx) macro.

Additionally, because you are passing `TRUE` for `bRegTypeLib`, it will also run the registry script identified by [`DECLARE_REGISTRY_APPID_RESOURCEID`](http://msdn.microsoft.com/en-us/library/005kd57z.aspx).
A good way for finding out this is to download the [Process Monitor](http://technet.microsoft.com/en-us/sysinternals/bb896645.aspx) and set it up to monitor registry changes (I'm assuming this is possible, it was in the older tool `RegMon` at least and this is the replacement) and then you do one `RegisterServer` and one `Unregister` and you'll have the complete list.

You'll probably have to set up some filters to filter out the stuff you don't want to see but should be easy to do.