GDSI Attach -N- Checkout? from Geller Data Solutions is an add-in for Microsoft Outlook and Interwoven FileSite allows you to have a document checked out and email it at the same time.
There is still a major fraction of industry that refuses to accept the full efficiency and economy of the Internet. Sure, they might be using email and Google search, but that's about it. I'd like to create a list that spans various cross-sections of industries that are still missing the big picture. Feel free to chirp in with any other examples.