Self-sending spam is unsolicited e-mail that looks like you sent it to yourself: your name appears on the "from" line as well as the "to" line. For example, Benjamin Googol might receive a message addressed to "email@example.com" that purports to be from "firstname.lastname@example.org." In some cases (especially if you use one of the most common e-mail services, such as Hotmail or Yahoo) a message may appear to be sent from your exact e-mail address.
Self-sending spam is one version of e-mail spoofing (disguising a message's "from" address so that it appears to be from someone other than the actual sender). The sender manually constructs a message header with their chosen information in it. E-mail spoofing is often sometimes used legitimately, for example, by someone spoofing their own address to manage their e-mail. However, spoofing anyone other than yourself is illegal.
Senders rely upon two factors - curiosity and a positive emotional response - that make the recipient more likely to open or even respond to a message that seems to be from someone with their name. A recent study at McMaster University found that people respond more positively to e-mail messages sent (at least apparently) from people with names similar or identical to their own. Researchers, who sent out thousands of requests for simple information, found that the response rate was over 10 per cent higher for messages sent using the exact name of the recipient as the sender. Even if only one name matched that of the recipient, the response rate was higher than for messages from someone with a different first and last name. However, as people receive more of these messages and the novelty wears off, it is unlikely that self-sending spam will continue to elicit any positive response.