Spam is simply a jargon term for unsolicited email, typically of a commercial nature, SPAM means receiving unsolicited electronic mail, usually advertising some product, service, business, scheme, website, etc. SPAMming via other means (e.g. usenet) is a different problem which we do not tackle here.. Spam costs very little for the sender, as ISPs and recipients incur most of the costs of transmitting it. Spam can be costly to your company, both in network resources and in employee time. Recent surveys show that 40% (or even more) of email to businesses is Spam.
Using Anti-Spam or Spam filter Email software to blocked spam is a good method.

How to identify a spammer?

While no filtering system is perfect, you can greatly reduce the number of spam and junk e-mails that you receive using your mail program's filtering function. simply look at the e-mail header, find the source host name (this may take practice because spammers try to hide the actual host name) or address and type it into the "Whois" utility. Or, if you are comfortable using a UNIX shell and have this kind of access, you can issue the Whois command from there.
Do not rely on the e-mail's return address. This is much too easy to fake. The other information in the e-mail header is more useful and more likely to lead to the actual sender.
You must be worryed by spam, just look at How to get rid of junk e-mail, spam

Free Email is web-based email, (e.g. Hotmail.com, Email.com). Free Email will allow you to setup email addresses with your domain name and check them via the internet.

POP3 stands for Post Office Protocol version 3. It is the standard means by which e-mails are received to your computer for viewing. POP is used to provide simple remote access to mailboxes. POP3 is the latest version of POP. With POP3, once mail clients connect and download their messages, the messages are typically removed from the server and stored on the client's local machine, but we offer a SpamWeed for POP3 software for you. It can block spammer easily using POP3 techenology.

SMTP is an acronym for Simple Mail Transport Protocol, which defines the mechanism for exchanging mail across a network. When a Mail User Agent (MUA) wishes to send mail across the Internet, it first passes mail to another machine called the Mail Transport Agent (MTA). This MTA communicates with other MTAs on the Internet using SMTP. SMTP is spoken via port 25 of the MTAs,You can have our trial version SMTP Server software for free. You will find its powerful and easy-to-use function and learn more.