<!--[if (gte mso 9)|(IE)]>

I've seen this appear in a few emails I get, because I'm all cool I always view the source of email campaigns that interest me.

Does anyone know what the specific logic means, its targetting Outlook, but I've never seen the (IE) part before.

I'm guessing its used for clients that don't support max-width, as it usually appears to conditionally wrap a container table with a fixed width.