Well, not really. It would back up emails server quite a bit. Email was always intended for messages, and adding binary attachments was really a "hack" and slight misuse of the technology. File transfers were, and still are, supposed to go over the file transfer protocol (FTP), or a variation thereof. High speed access (10mbit+ speed cable/fiber -- not DSL) has allowed files to transfer over HTTP for a while now, but that's honestly misuse of that protocol, too. That was intended for web browser content, not file delivery.
Dropbox is one of those HTTP services. Free up to 2GB:
http://www.dropbox.com
And it's not annoying like those other services typically used for underground shenanigans (Rapidshare, Mediafire, etc). Those sites are filled with ads, force you to run scripts/plugins, make you wait around for downloads, etc. I understand wanting to cash in one their service, but that's ridiculous, and there needs to be a less intrusive method. Dropbox is doing well with "less intrusive" right now -- and hopefully it will stay that way.
Using email for large file attachments is like using your car to pull a trailer. Yes, it probably can be done, but it's far from ideal. You're better off using the proper tool for the task, such as a truck.