The major problem with analytics cookies is that they don't represent a person. They represent a device, or in some cases they represent a profile on a device. This often muddies up your analytics reports because a user might sign up for a newsletter, or request a demo, or download a lead magnet on one device, but then converts on a different device.

Most analytics tools will now report that this second device, that had its first session come from an email campaign, performed your conversion action. I don't know about you, but somehow I doubt that purchases or trial signups in someone's first session is the result of "newsletter_nurture_campaign_x".

How to Connect Email Data with Web Data

Most email platforms let you add dynamic bits of text into their templates. If you have ever received an email that starts with Hello {first_name}! you know exactly what I mean :)

We can use that feature to add some sort of identifying information to email campaign links that go beyond utm_source, utm_medium, utm_campaign. That bit of information is the email system's internal ID for the person you are sending the email to.

Essentiall we will turn

https://obsessiveanalytics.com?
  utm_source=mailchimp
  &utm_medium=email
  &utm_campaign=newsletter

into

https://obsessiveanalytics.com?
  utm_source=mailchimp
  &utm_medium=email
  &utm_campaign=newsletter
  &mc_id=65eae27c7e

How Does That Help Increase Accuracy?

Lots of analytics tools will allow you to define a list of identifiers that cause someone's profile to merge. So lets say someone visits your website and has a new anonymous ID generated by your analytics tool of choice: 3c95f15d-9811-41e1-8203-6ca78b8bab54. That same person then signs up for a newsletter, trial, account, etc. with [email protected]. Now John clicks on the confirmation link on a different device or browser which makes John look like a new visitor with another new anonymous ID f949d3ad-092d-44de-bff2-56f9f153810d.

Well, if John's click through URL contained their mailchimp ID, you can now stitch that all together because:

1. You know 3c95f15d-9811-41e1-8203-6ca78b8bab54 is connected to [email protected]
2. Mailchimp tells you that [email protected] is connected to mailchimp ID 65eae27c7e
3. The pageview from f949d3ad-092d-44de-bff2-56f9f153810d tells you that it is connected to 65eae27c7e from that extra URL parameter

Depending on the settings and support of your analytics tools, this will now treat all those IDs as the same person and therefore show you the whole customer journey. If your analytics tool doesn't let you do that, you might have to do some SQL in your data warehouse to do this kind of computation, but at least all the data is there to connect the dots.

How to do this in Mailchimp?

The exact nature of template strings available varies from tool to tool, but in Mailchimp's case it is *|UNIQID|* to refer to your contact's unique ID.

Since we're adding this to a link URL it is important that you don't use something like *|EMAIL|*. You don't want to transmit someone's email address in plain text in a URL. That's a big data privacy no-no!

So here's how you can add this contact ID to Mailchimp's templates:

As you can see, I added the same *|UNIQID|* block to the link text. This is just for illustrative purposes so you can see it directly in the email:

Clicking on this link sends us to our new tagged URL with mc_id=65eae27c7e in the URL!

Conclusion and Next Steps

With this in place, you can do a bunch of new things, such as easily differentiating new vs returning visitors by checking for the presence of mc_id=.... in the URL, or integrating this ID into an ID Graph as described here.

It also allows you to provide more accurate user numbers, because you don't even have to wait for this second anonymous ID f949d3ad-092d-44de-bff2-56f9f153810d to perform some identifying action like logging into an account. You already know that this person isn't a new user. You will also get more accurate session numbers, because f949d3ad-092d-44de-bff2-56f9f153810d did not start a new session (assuming that the time between the last action of 3c95f15d-9811-41e1-8203-6ca78b8bab54 was less than X minutes before the first action of f949d3ad-092d-44de-bff2-56f9f153810d).

Side-Note: My Numbers Are Going Down! What's Going On?

It is important to note that implementing such a system will reduce numbers that lots of organizations use as north star metrics or key performance indicators (KPIs). Arguing why chasing after session counts or new website visitors is a bad idea is outside the scope of this post, so I will just say that you should focus on making decisions that are based on the best available data, not necessarily the data that makes you feel good.

What information is more useful to a business:

1. I had two new visitors, one desktop user from paid search campaign X and one mobile user from email campaign Y. Each vistior had one session each. The first visitor signed up for a newsletter. The other signed up for a trial.
2. I had one new vistior that came to our site from search campaign X, signed up for a newsletter and then, in the same session, also signed up for a trial. We also know that this user uses both a desktop and mobile device to interact with our website.

Option (1) would tell you that paid search is a great way to get newsletter subscribers, but doesn't help with trial signups. I would argue that this is a very wrong conclusion and can actually hurt the business.

I hope you found this informative. If you have any questions, feel free to contact me here or hit me up on LinkedIn.