Whether you get junk mail or not also seems to depend on how common-sounding your e-mail address is. For example, if your name is John Smith, then you will get a lot of junk if your address is something like
jsmith@hotmail.com. But if you make your e-mail address
JS66260755@hotmail.com, then you won't get much. I suspect that some of these companies that send spam generate e-mail addresses by taking a list of Last names and adding different letters or different first names in front of them, or some other common way that people use to come up with addresses.
Spam is a luncheon meat that comes in a rectangular can, similar to corned beef.