Google Tag Manager allows you to easily send all products to an external resource, by using the dataLayer, and a specific tag.

But what if you want to fire a tag only when a specific product, or set of products, have been purchased?

I worked out an easy way to get it done, using macro's and dataLayer.

Using Exact Target it is very possible to track conversions, using a basic img tag which passes some xml to the tracker.

You can read about how/what is required here: http://help.exacttarget.com/en/documentation/exacttarget/content/conversion_tracking/

Making this work with Google Tag manager is a bit tricky, but very possible

The process can be done in 3 easy steps:

1. Capture the relevant passed params from any cliked url

2. Pass that data to teh datalayer

3. Use the data in GTM