What is the difference between in-proc and out-of-proc?

In-proc - Com object is present within application process
Out-Proc - Com object has it's own process area In-proc - E.g. Activex Dll
Out-Proc - E.g. Activex exe In-proc - Faster
Out-Proc - Comparitively slower In-proc - Useful for local com
Out-Proc - Useful for remote com