A very good practice for any e-commerce or content syndication site is to build an email subscriber list. I recently had to whip together a quick way of doing this, and didn't have the time to build a database driven system. I used PHP and a text file to build an easy subscriber system. Each new email gets appended to the text file, simple as that.

Assume we have a text file called 'subscribers.txt', then here is the code. I use a function called checkEmail (explained on this site) to verify the authenticity of the email address.

$emailaddress = $_POST['Email'];

if(checkEmail($emailaddress)) {
	$f=fopen("subscribers.txt","a"); //open text file for appending
	fwrite($f,$emailaddress . "\n");
	fclose($f);
} else {
	echo(" - Invalid email<br />");
	echo("<a href=index.htm>Try again</a>");
	die;
}