I used to do this (back in 1998-2002 or so), but it doesn't really make sense to do so, unless you intend to actually use them differently, or if your domain so

I used to do this (back in 1998-2002 or so), but it doesn't really make sense to do so, unless you intend to actually use them differently, or if your domain somehow makes more sense with ".net" after it or something.