Most likely I don't have to explain what spam is. Surely you have seen more of it than you really care for. What can be done to reduce it? Quite a lot really.
In November 2007 I decided to start a little experiment.
On the 14th I've put two e-mail addresses on my main page with the intention to attract spam.
Not to worry, it were disposable addresses.
Now the experiment is done they are simply discarded and I will never see spam on them again.
Because my ISP has a pretty good spam filter I had to direct the addresses directly to my spam box, otherwise it might influence the test result.
Much to my surprise the easy target started drawing spam within 3 days! I knew it was a sitting duck and it was intended to be one, but that it would take only 3 days for it to be discovered by the bad guys was quite an unpleasant surprise to me.
On 24 November 2007 I've started a new experiment.
I've posted a message in a commonly visited usenet group using a new, unique, disposable e-mail address.
Let's see what happens with that address.
Well nothing much happened. It's 5 February now and still no spam on this address. Obviously the particular news group I've used isn't visited by harvesters very often.
And on 24 November 2007 I've started yet another experiment.
My main page was indexed by search engines only 2 days after I've put the new unique spam trap address on it.
Possibly the spam spider uses these results to harvest new victims.
Now I've created a separate page, which will not be indexed by search engines (if they obey the rules that is).
Finally on 31 January 2008 the first spam arrived. It took them long enough, but they've found it after some 2 months. Maybe some harvesters obey the robots.txt file after all.
The experiments above clearly show that it is crucial to be very careful with your e-mail address on the internet at the penalty of being flooded by spam.
This method is quite safe, after several years of use I still don't receive any spam on it.
And even if I do get spam on it in the future, it still is a disposable address. I can change it whenever I want.
It is a simple program, and even if you're a novice to Javascipt you probably see what it does.
First two variables are assigned with the two portions of your e-mail address.
Then these two variables are used to write a piece of text to your document, containing the href="mailto: part and the human readable part of your e-mail address.
This results in an apparently normal looking clickable e-mail address on your page, but this time your html code doesn't contain the dangerous mailto tag nor does it contain a readable copy of your e-mail address.