Fighting spam is a never-ending battle. You develope a strategy and there is always a counter-response. Fortunatly taking several low-effort steps that make spammers actions ineffective or difficult puts you at an advantage.
FIGHTING FIRE WITH FIRE
If a spammer had to gather e-mail addresses manually and send ads one at a time, the whole enterprise wouldn't be worth his effort. Automation gives him a huge boost in this area though.
OK, so two can play at that game.
Since spam is made possible by programs, programs can assist in fighting it - and, fortunately, there are many currently available. Before learning how to use them though, it is helpful to know how spammers do their dirty deeds and what simple actions a user can take to counter them.
One of the most effective tools spammers have are called spambots - these are programs programs that automatically browses websites looking for e-mail addresses, which it then "harvests" and stores in large database lists. The lists are then either used directly for marketing purposes or sold, often as CDs listing millions of addresses.
There are no perfect ways for stopping spambots, but there are several effective techniques to at least slow them down.
MISDIRECT
If you don't expose an e-mail address to harvest, you will not be harvested. But in a time when blogs, forums and other public sites are heavily used - and most require providing an e-mail address to post if not to read - it's difficult to avoid.
So for those public venues, define and use an address where you intend to receive no personal e-mail. After responding to the sign-up confirmation email you don't have to care what goes there any more. Keep another for personal use and give it only to trusted individuals and vendors.
A word of caution: Hotmail, Yahoo and other large providers have often been used for this purpose. Some sites are wise to this and won't allow addresses with @hotmail.com, for example. Fortunately, there are dozens of free e-mail providers and you don't have to use the same one every time.
CAMOUFLAGE
Spambots are very clever, but they are not human. They can not make subtle distinctions or inferences unless they are programmed to do so. Often, disguising a publicly visible e-mail address is enough to cause the spambot to bypass you. They are frequently programmed to look for character strings like John_Example@somecleverdomainname.com. Programs only do what they're instructed, so even so simple a change as John_Example_at_NOSPAMsomecleverdomainname.com is enough to fool them.
Even if your disguised e-mail address is harvested, at a minimum the address has to be 'scrubbed' in order to be used. Scrubbing routines are even harder to write than spambots, because there are so many possible variations. (NO_SPAM, NOSPAM, no*spam and many that are much more clever. Be creative!) Those variations are usually simple for humans to decipher, but again programs only do what they have instructed to do.
The method does have potential drawbacks. Humans have to strip out the extra letters and insert the @-sign (in the above example) - something they sometimes fail to do out of failure to understand the need to, or because they simply hit Reply To. Also, since many e-mail confirmation systems are themselves automated (by software, naturally), they too will fail to deliver to the intended address.
A variation on the technique can be used not only by web site designers but (to an extent) users. You can usually configure your e-mail account to make the receiver see your e-mail address as anything you wish, regardless of the actual address. After all, that's how spammers often disguise themselves, too.
FILTERS
Once you make the effort to create an e-mail account and advertise it to your friends, business associates and trusted vendors changing (or even disguising) it can be undesirable. That puts you in the position of making high cost efforts for low reward - exactly the role you want the spammer to be in, not you.
Spam or Junk Mail filters to the rescue.
Filters examine every e-mail before it's delivered and apply complex algorithms to determine whether one is junk or not. They're configurable so that e-mail from senders listed in your address book pass through to your Inbox, with others directed to a Junk folder.
Though imperfect, those algorithms are reviewed often by e-mail providers and evolve to capture more junk and fewer valid messages. And, when reviewing the junk mail folder, some allow you to specify whether they 'guessed' correctly. Your answers allow the algorithms to make better guesses.
RAISE THE PRICE
Eventually, even hard core spammers get tired of programming variations to bypass the hurdles thrown in their way, deciding the effort isn't worth the reward. The trick is to make the cost of their effort much higher than the reward, while making the cost to you low and the reward high.
Spammers haven't surrendered, but progress to date has been impressive.
