Collect useragent and ipaddress data from friends. I created this note redirect script to do the same. They were pointed to this script saying that they will be shown a note they must read.

noteredirect.php

<?php 
/*
 @scriptName: noteredirect.php
 @author: Santosh Kumar
 @authorURL: http://sntsh.com

*/

  // set the content type which is read by browser
	header("Content-type: text/plain");
	
	// must set the timezone so that you don't confuse about time later
	date_default_timezone_set('Asia/Kolkata');

  // define IP address and user agent
	$ip = $_SERVER["REMOTE_ADDR"];
	$ua = $_SERVER["HTTP_USER_AGENT"];
	
	// define timestamp
	$fulltime = strftime('%c');

  // write them at once
	$format = $ip . " __on__ " . $fulltime . " __with__ " . $ua . "\n\n";

  // write them to file, NOTE: They must already have been created
	$fp = fopen('noteredirect.txt', 'a');
	fwrite($fp, $format);
	fclose($fp);

  // redirect to the real note.. or wherever
	header("Location: https://twitter.com/sntshk");

?>