Spam can be found everywhere and I am not talking about the spam that you find in cans that are edible. This spam is ugly, horrible, and it can hurt your website. When people go around posting total crap into your website, forum, or blog, the content is considered as spam and the posters as spammers. You will also find spam in your email folder and some even have special spam folders that will mark some emails as spam before you get to read them. These anti spam services provided help protect you and it can prevent opening mails that can give you viruses and crash your computer.
Mail systems like Yahoo! and Gmail provide anti-spam software and service to help you mark spam without much problem. It is true that some emails will still get sent to your inbox, but there is always an option to block that email address or permanently mark it as spam. Thank these sevices to help you stop spam. And if you own a website there are plenty of ways to stop spammers from coming onto your site by blocking links with certain scripts or mods. Good luck with the fight against spam!