If you are looking to build an email list, and want to be able to use custom variables in the emails that you send out, then this guide is for you. Here are some example use cases:

  • Tag subscribers to affiliates, so that you can add their Clickbank hop ID to all your links, in all your future email broadcasts/autoresponders
  • Track total revenue based on where you acquired a subscriber. E.g. track Google Analytics variables by appending them to all future links that you email out

I chose Aweber because it is a great email marketing service that is very popular because of the advanced features that it allows.

One great feature is the fact that Aweber allows you to use custom variables, but many people don’t know or don’t use this feature. You should though, because this allows you to a lot of cool things. In this post, I’ll show you how you can automatically track who referred a subscriber to you, and insert their affiliate link in your emails. This is good to have for merchants, because you can run an email list on your sales page, and still get affiliates to wholeheartedly refer visitors to you still.


  1. PHP
  2. Aweber

To do this, you’ll need to setup a custom variable in Aweber. Let’s call it “ref”. Here’s a screenshot of where to do this in Aweber.

aweber creating a custom variable

Now that you have a custom variable, we need to use it in our opt-in forms. The problem here though, is that the form builder in Aweber doesn’t allow you to insert PHP code (which is what we require for this to work).

So just create your opt-in form as per normal, but without the ref field (you’ll see it in the form builder). Now this is where things differ: when it asks you to publish as Javascript or HTML, choose HTML. Grab that code, stick it on your website where you want it, and paste this line of code right before the </form> tag. Remember to change the words YourDefaultRefGoesHere. This will set a default ref to use, just in case the visitor got to your form without a referrer (Thanks Mike!).

Note: A cookie-version of the code has been added (Thanks to Chris’s suggestion!). What it does is to cookie visitors, and then read the cookie when they visit your page again. Instructions within the text file.

  1. See the code here (txt file)
  2. Cookie-version of code here (txt file)

Alert: The only drawback for this method is unlike the Javascript method, you won’t be able to track impressions on your form. The benefit is that EVERYONE can view a HTML form, whereas some people may turn off Javascript support in their browsers, or have a browser that does not support Javascript, so they won’t be able to see your Javascript form.

Now that the form and variable is complete, we’ll need to actually use it. The following screenshot shows you how to do so. Simply create a broadcast or followup message as per normal, but click on the “Personalize” link, and choose your custom variable, as shown.

You’ll notice 2 variants of your variable listed, and here’s what they mean. For our case, we can just use the first version, which is {!custom ref}. These are basically the only two variants that you’ll be faced with:

  • {!custom variable_name}: Whatever information is stored in the variable_name custom field
  • {!custom_fix variable_name}: Whatever information is stored in the variable_name custom field, with the first letter of each word capitalized

After this, anyone who gets referred to your page like so: YourPage.php?ref=jack will automatically have “jack” stored into the custom variable of “ref”. In future, anytime you want to dynamically insert the referring affiliate, just use {!custom ref} in your emails.

An example link will be:

http://www.yourdomain.com/product.php?ref={!custom ref}

Viola. Now you can dynamically insert affiliate links in your emails or track referrals with Aweber! If you don’t already have Aweber, I highly recommend it because of the features and performance that it offers. The above technique is just one small feature that Aweber offers – think about Geo-targeting, or split-testing…just some more of the advanced features that Aweber offers.

Update: This works if you’re a Clickbank affiliate as well. Just change “ref” to “hop”, and you can use the following URL structure:

http://{!custom hop}.MERCHANT.hop.clickbank.net

Now your affiliates who refer visitors to your email list can continue earning their rightful commissions!

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