Spam is the term used to describe unsolicited email.  The term originally came from a Monty Python sketch whereby someone went into a cafe and the menu had Spam and chips, Spam and salad, Spam and egg ... i.e. Spam with everything.  When newsgroups first started, marketers started posting "off topic".  For example, people selling gardening equipment would not just post to gardening related newsgroups, but also to fishing newsgroups on the premise that fishermen have gardens too! 

Needless to say, people soon got fed up of every other post being from someone selling something. 

The Internet is awash with people offering to sell you millions of email addresses for a few hundred dollars.  Sounds too good to be true?  Off course it is!!!! 

The first problem is that these people selling these lists obviously use them too - and so millions of people have been offered the SAME list. Statistically a large number of people are likely to have already bought it, and so the people you are mailing are already receiving loads of unsolicited emails on a daily basis (I receive about 20-30 every morning - all of which are deleted without reading them!) 

The second problem is how they procure the addresses.  The most common method is to use so called "Harvesting" software.  This goes off and searches newsgroups and retrieves the senders email address.  People who got sick of receiving unsolicited mail started adding words such as "NOSPAMPLEASE" into their email address - e.g. adam@eve.co.qz  would become adamnospamplease@eve.co.qz.  Very easy for a human to decode, not so easy for a computer. 

Harvesting software then became more sophisticated and used pattern matching to remove the additional words.  How stupid!!!!  The poster obviously wrote their email address in that way because they did not wish to receive spam and yet people still think that this person will buy from them by ignoring their request!  

The third problem is how you are going to send that many emails!  Legitimately sending mail via your ISP will only go through at about 2,000 an hour.  So to spam 1 million people will take you over 500 hours!  Your ISP is likely to spot that something odd is going on and pull the plug long before then! 

The route that many spammers take is to illegally route their mail through several companies servers - without their permission.  This is not recommended!  Supposing you send the mails anonymously - how are customers going to get in touch with you??

Dynamic Mailer (ODBC) is designed to handle "opt-in" emailing lists.  That is, people who have REQUESTED to receive email from you, or who you have previously done business with - and whom you have more information about than just their email address!  

If you haven't already done so, you should add a section to your website where people can sign up to join your mailing list.