SPAM is not a technology issue, it is an Internet control process and policy issue which will require Government intervention (Internet laws) and cooperation between Internet companies, businesses and International Internet Standards Committees... which all exist today.
First off, in defense of the spammers, everyone has a right to market their product or service. The flip side is that everyone also has the right to reject or block unwanted marketing material. This is why some people decide to build gates around their home or hire a secretary to screen their business calls and letters.
Spammers do what they do because for one reason, money. Companies pay spammers lots of money to send their messages. Of course spamming is illegal in America. But there are many other countries spammers can work in, like Russia and China, who turn a blind eye to spam operations. After all, it ultimately benefits the their economy. Spammers make money, spammers spend money, everyone is happy.
Solution Options:
1. Take anonymity away from Internet users.
Imagine, everyone would suddenly be polite and bad people would get caught alot easier.
Probably not a real practical solution but it would make it possible to trace the source of spammers and Internet predators in general. Today, offshore and over seas spammers can easily hide themselves behind layers of anonymity. So it is difficult, if not impossible to find the people responsible for the spam.
2. Require all mail servers to be registered and have a Operating Permit.
***Note to non-technical reader: Mail servers are NOT your personal computer. Mail servers are operated by companies such as your Internet Service Provider or highly technical individuals and are used to enable the sending of email.***
All registered mail servers will be stored in global database(s). Companies or individuals who operate mail servers (Google, AOL, IEA, Joe Bob tech geek, etc..) have the option to ONLY accept email from registered mail servers.
***Note to techies: The global databases can be like the root name servers on the Internet today but even more distributed and difficult to take down with DDoS attacks. In fact, if the databases were part of the root name servers then people who DDoS them would only succeed in hurting themselves as name resolution would be impacted ***
In order to register a mail server one must obtain a FREE operating permit/ID. To acquire the Permit one must provide information and be verified, like a drivers license. The ID will be HIGHLY secretive and encrypted. This permit will be entered into the mail server. The permit will also be entered into the global database by the Registration Authority. If a company, such as AT&T has 2,000 mail servers then each mail server can use the same ID/Permit if they want.
The logistical details of this concept can easily be worked out.
Now, say a spammer uses a registered mail server to send spam... guess what, it gets removed from the global database for "x" time and a notice sent to the registered contact.
Say a a spammer breaks into a mail server owned by someone else and uses it to send spam, then the real owner is notified that mail server "125" was removed and can fix the problem.
The concept is similar to a National "do-not-call" database, but in reverse. A national "do-email" database, even a global "do-email" database.
