Unsolicited email, fax, or other electronic submissions are generally destroyed unread. We really hate that. If you have any questions or concerns regarding an electronic submission, ask us. We prefer email over floppy submission. We can deal with just about any format, though, so if you can't get it to us in those easily, we can work something out.
Paper clips are fine.
If you don't care enough to submit directly to us, we don't care enough to read your stuff. If you're capable of sending a submission as an email attachment that we can decode, in a file format that would make our lives easier, that's the way we want it. This includes things like sending material via registered mail, courier, or overnight delivery service. If we want material from a contributor via one of these methods, we will request it in advance. It takes us a certain amount of time to read, review, and decide on submissions.