I have written a lot recently about the importance of mailing lists. Last Friday, in fact, I explained about how I had been working on a lightbox solution for optins using the You Can't Block This script. The only problem is that I have been worried about bugging my normal readers and tarnishing my brand.

Sure enough, I got this thoughtful comment from a loyal reader (Alex The Big Blogger):

I’m not a fan of Popups, I consider them a little bit spammy, although I’ve tested them out on my own blog and I too have seen good results. I’ve made them with Aweber and set a delay to the apparence. On this way the visitor fisrt starts reading the post and then he gets the popup. Getting a popup as the first thing when i come to a site sets me up and makes me walk away.

That is exactly what I am worried about — but I like the idea of a delay.

Then it occurred to me that I could just put some php code around the JavaScript based on the referrer to determine if the lightbox appeared.  For my initial experiment, I am only showing the opt-in box to users from StumbleUpon, Google search, Yahoo search and MSN search.  That way, I should not be offending my regular readers. (I know I am not the first person to have this idea, by the way).

In addition to that, I have the popup set to display once per browser session. That should allow for minimum annoyance.

I will let you know how it goes. I have added some Google Analytics code to the popup box html, so I should be able to get some decent stats on the performance.

One issue — not all browsers are configured to report the referring website. For our current experiment, those visitors will not see the box. I may change this behavior later.

In case you are interested, here is the trivial php code to manage who sees the popup:

$referer = strtolower($_SERVER[“HTTP_REFERER”]);
if ( strstr($referer,”google”)||strstr($referer,”yahoo”)||
strstr($referer,”.live.”)||strstr($referer, “stumbleupon”))
{
?>

— POPUP SCRIPT HERE —

(Special thanks to Josh Spaulding for help with troubleshooting)

Have a great day!
Mark