Some have argued that the most effective way to put an end to spam is by contacting the service providers that are responsible for bringing the content to your desktop. Of those, the registrar is often the most effective administrative body to contact. This is because often the spams are sent from hacked machines, whose administrators may be slow or unable to respond to the problem. Registrars on the other hand, as ICANN-accredited administrative organizations, are obliged to uphold certain rules and regulations, and have the resources necessary for dealing with abuse complaints.
Tracking down a spammer's ISP and reporting the offense can lead to the spammer's service being terminated. Unfortunately, it can be difficult to track down the spammer—and while there are some online tools to assist, they are not always accurate. Occasionally, spammers employ their own netblocks. In this case, the abuse contact for the netblock can be the spammer itself and can confirm your address. Examples of these online tools are SpamCop and Network Abuse Clearinghouse. They provide automated or semi-automated means to report spam to ISPs. Some spam-fighters regard them as inaccurate compared to what an expert in the email system can do; however, most email users are not experts.
A useful free tool that may be used in the reporting of spam is also available (Complainterator). The Complainterator will send an automatically-generated complaint to the registrar of the spamming domain and the registrar of its name servers.
Historically, reporting spam in this way has not seriously abated spam, since the spammers simply move their operation to another url, ISP or network of IP addresses.
Consumers may also forward "unwanted or deceptive spam" to an email address (spam@uce.gov) maintained by the FTC. The database collected is used to prosecute perpetrators of scam or deceptive advertising.
Some advocate responding aggressively to spam—in other words, "spamming the spammer". The basic idea is to make spamming less attractive to the spammer, by increasing the spammer's overhead. There are several ways to reach a spammer, but besides the caveats above, it may lead to retaliations by the spammer.
1. Replying directly to the spammer's email address. Just clicking "reply" will not work in the vast majority of cases, since most of the sender addresses are forged or made up. In some cases, however, spammers do provide valid addresses, as in the case of Nigerian scams
2. Targeting the computers used to send out spam. In 2005, IBM announced a service to bounce spam directly to the computers that send out spam. Because the IP addresses are identified in the headers of every message, it would be possible to target those computers directly, sidestepping the problem of forged email addresses. In most cases, however, those computers do not belong to the real spammer, but to unsuspecting users with unsecured or outdated systems, hijacked through malware and controlled at distance by the spammer.
3. Leaving messages on the spamvertised site. Spammers selling their wares need a tangible point of contact so that customers can reach them. Sometimes it is a telephone number, but most often is a web site containing web forms through which customers can fill out orders or inquiries, or even "unsubscribe" requests. Since positive response to spam is probably much less than 1/10,000, if just a tiny percentage of users visit spam sites just to leave negative messages, the negative messages could easily outnumber positive ones, incurring costs for spammers to sort them out, not mentioning the cost in bandwidth. This was the approach used by the now-defunct Blue Security's Blue Frog service: it looked for web forms on those sites and filled one form on behalf of the subscriber for each spam received, thus overwhelming spammer sites (Blue Frog service had up to a half million users). Ironically, it was Blue Frog's effectiveness that brought it down, by attracting a massive, retaliatory denial-of-service attack from a spammer who refused to fold. After the demise of Blue Frog, other services have been trying to replicate its ideas, while avoiding its shortcomings.
