Spammers get email addresses from web pages using programs called spiders which tour the internet capturing letter strings with the “@" character in it.
Signing up for extra information at some sites and giving your email address can also get you a flood of unwanted mail, but although it feels like spam, it is, or started as, “Opt-in" email.
However, recent legislation in some countries can redefine this as spam if it fails to have certain features, like return address and physical address (of course, just what is required depends on country).
Overcoming that kind of spam is a challenge after you have signed up in a weak moment, although there are a number of programs that attempt to solve the problem. Just one is K9 from http://keir.net/k9.html
But consider this situation: you have a web page and you expect a flood of visitors, and need to put your email address there.
But how do you keep it clean?
Well remember the spiders look for an @ in the string.
We can put an alternate symbol in its place. So meandherATthere.com sits on my web page. With that particular one, we assume that the visitor has the nouse to preplace the AT with an @ and not think it is a new way to write email addresses, and the program would take care of it, and they needent do anything!
Rather than go through all the alternatives here, you will find a list of different methods and some comments about each one, on the site www.takeyoursiteup.com .
May your site not send you any more unwanted visitors!
David is a former Medial Scientist who got into programming and web development and lives in South Australia. His yahoo box gets a regular stream of spam, and doesn't want any more!