Spam, or unsolicited “junk” email, is a common problem for people connected to the Internet. While it’s pretty easy to delete spam, it can take a long time to sort the spam from the non-spam messages, and worse, some spammers have also started attaching viruses to their spam messages. So, it’s best to avoid being spammed in the first place.
Jennifer Hodgdon lead consultant at Poplar ProductivityWare has written a thorough article on the SPAM problem issue and how to avoid/reduce it.