1) Database Cleansing. There are many key influencers that will determine the quality of your recipient database, and in turn the success of your email deliverability. These include your recipient acquisition policy, bounce management, prompt processing of un-subscription requests and spam complaint management.

A number of data cleansing issues can be handled automatically by your ESPs. For example, if a spam compliant is reported most ESPs will track this and automatically make the subscriber inactive in your list. 

Having a good reputation is under your control. The ESP broadcast platform is only half of the deliverability equation; best practice on the sender’s part makes up the other half.

2) Sender Reputation. A sender’s reputation is based on message content, complaint rates, presence of spam traps, bounce management, the number of rejected addresses and unsubscriptions. You can measure your sender reputation free via IPs or website domains, such as http://www.senderscore.org or http://senderbase.org.
 
Reputation scores will show you what level of deliverability you should expect based on your reputation. You can also obtain information on the possible blacklisting of IP addresses, volume, existing spam traps etc.

Some providers, like Microsoft (Windows Live Mail) offer follow-up tools. Microsoft offers a program called Smart Network Data services (SNDS) to measure day after day the reputation of IPs by domain and volume according to spam complaints and bounces. This program works thanks to user panels that are regularly used by Microsoft for the scoring and classification of emails received by their subscribers. According to the panel classification, IP or domain reputations will have a positive or negative impact.

Furthermore, some anti-spam lists allow you to verify if an IP or domain is blacklisted or grey listed. If an IP appears in one of these lists, results of email campaigns can be badly affected. If you want to be removed from this list, you should contact them directly via their website.

3) Performance Measurement and Statistics. Measuring campaign performance is essential in monitoring deliverability. Clicks, opens and conversions are a good indicator of possible spam issues, bad reputation or unknown blocking problems (without feedback). Looking at metrics by domain and can also help you identify any big blockages.

4) Message Content. This is often overlooked, but whether your email gets delivered or ends up in the spam folder depends partly on message content.  You should consider the HTML structure, image to text ratio and any dynamic elements. You can check your HTML on websites using W3C as a reference like http://validator.w3.org.

Providers such as Windows Live Mail, Yahoo Mail, Gmail or Mail User Agents like Outlook 2007, Thunderbird and Lotus Notes will judge whether the email should be considered as spam in different ways.  The HTML and content (images, spam words, URL….) provides you with a “spam score”, and success of your campaign will depend on this spam score. Scoring tools and software are available for free on the internet. The most commonly used spam filter solution is the SpamAssassin tool: http://spamassassin.apache.org.

5) Keep your Emails Relevant. Arguably the most important point to remember; sending irrelevant emails will significantly lower your chances of getting your message into the intended recipient’s inbox. To achieve email relevance make the most of email segmentation and targeting techniques, decide on a sending frequency and stick to it, respect any unsubscribe requests and remove dormant address.

Your email deliverability can make or break the success of your email campaigns so it is important to get it right. Your ESP should be able to guide you on best practice in this area but ultimately email delivery is a marketer’s responsibility.

To really generate cut through, messages must be relevant and targeted, data must be kept clean and segmented, and email performance needs to be regularly analyzed alongside your deliverability measurement.