Segmenting your subscribers allows you to better group the emails you send, track the success of campaigns and, generally, keep them around for longer.

It's important to note that you need to think about segmenting subscribers from the moment they begin: from the moment they actually become subscribers.

There are lots of ways you can segment your subscribers but here are three broad approaches you can use. As you get more sophisticated you will likely use all three but using even one is a good place to start and will put you ahead of most of the competition!

1. USE YOUR CUSTOMERS' ATTRIBUTES

This is the simplest place to start. Using your customers' specific details such as their age, sex, previous purchase value, the number of purchases, where they live and their birthday you can create a lot of different, relevant segments.

Collecting these sorts of details can happen in one foul swoop or it can happen in increments. As your relationship with an individual customers grows you'll likely need to (and want to) learn more about them. A general rule of thumb is to keep things simple up front so as not to ward subscribers away.

ASOS does a great job of showing how this can be done. They include a simple 'Men' vs. 'Women' submit button. This is a great example of getting your hands on some basic customer segmentation attributes without lifting a finger and without deterring customers.

Other data, such as past total purchase value and location can be tracked implictly whilst attributes such as age, favourite items / products or their relationships might have to be asked. YOOX provides an example of an extremely sophisiticated attribution tool, as described in chapter one.

Using your customers attributes is the most basic place to start but will give you a lot of power. Even ensuring you don't send Australian customers an email about the 4th of July or US customers a special for the Queen's Birthday puts you ahead in the game to ensure your emails are relevant.

2. TRACK YOUR CUSTOMERS' ONLINE BEHAVIOR

Keeping track of past purchases, what features a customer has or has not used, keeping track of their initial landing page and understanding the products a customer views are all basic examples of behavior you can track to provide more targeted emails.

When a cart is abandoned or multiple visits are made to a particular page you can use this information to send emails to customers at an individual level and ensure each email is truly relevant. This is really segmentation in it's purest form as your 'segments' no longer contain tens, hundreds or thousands of users but one!

Many businesses spend a lot of time using customer behaviour to influence on-site UI changes or the content that a customer sees but don't forget that you can use it to tailor your email marketing campaigns as well.

The best examples come from the likes of Amazon, who do this tremendously well:

Amazon use behaviour to influence both the on-site and off-site experiences and collect information about every user in really subtle ways. Now, as their offerings grow they can do this cross-device and beyond.

Another of their great campaigns is this one:

This one was originally mentioned on DBS.

Both tremendous examples of the power of tracking which products customer view and purchase and putting this data to work to send something personal to an individual customer.

Another example from a different category all together is this great email from Travelocity (originally mentioned on Clickz)

The national airline for Ireland, this campaign targets customers that have booked a flight recently and are heading to an Irish destination. Again, tracking individual customer actions allows Aer Lingus to increase conversion rates thanks to tightly-targeted deals. Savvy.

3. USE SOCIAL INTERESTS AND INTERACTIONS

Perhaps the holy grail, emailing customers based on their interactions with other users is extremely effective. At the top end of town companies like Facebook and Twitter have the ability to use their direct social data to drive these campaigns. Here's an example from Twitter that you are probably familiar with:

Here's a similar example from social-shopping site Svpply:

Thanks to the fact that 'social' is now ubiquitious, external companies (i.e. non-social networks) are starting to use this data to drive engagement, retention and acquisition. Gaming and other apps built on top of the Facebook platform are common users of social data when it comes to email but even typical, offline, businesses can make the most of social networks to capture new customers and email subscribers. Although not powered by an interaction on a social network this savvy campaign by RAPP UK for the Cancer Research UK's Run for Life uses Facebook and Twitter to create a 'viral loop'.