SPAM
Spreading
Spam is very similar to viruses. They both are spread through email and can be hazardous to you computer. Spam happens when you sign up for a site and that site sells your email. It also happens when the creators of the spam guess random emails to try and spread it.
Getting Around Spam
There are many ways to avoid spam. If you see an email with an attachment from someone you don't know don't open it. Also many email providers have filters on them to stop spam. Gmail has one of the best filters.