Techquickie just released a video giving the lowdown on SPAM, how it became so prolific, profitable and what is being done to stop it: Spam As Fast As Possible
They say the first SPAM message was sent over ARPNET (Advanced Research Projects Agency Network) and laughably it was stopped by being promptly rebuked by fellow members. Ironically, today any sharp rebuke replies to SPAM messages will most likely flag your email address as an active email and you'll end up receiving even more SPAM emails.
Recognizing that the cost of sending an email was so cheap and easy to do, SPAM emails started being sent like crazy. Even though so few people actually interacted with these emails, so many are sent that it's actually profitable for the spammer. And so is the short story of why there are so many junk emails being sent to us every day.
Techquickie points out how dubious advertisements can fool people into giving out their email addresses, and then those spammers sell your email address to other spammers.
Dubious advertisements can also lead people to malicious websites that convince them to sign up for... stuff, using an email address which is then harvested.
EmailonDeck's value really stands out. By using a temporary email address you can keep your real email address protected from spammers and from them selling your actual email address to others.
EmailonDeck securely deletes all emails after use and allows you peace of mind knowing that you always have a temp email available to you use whenever you want.