Tipsheet: HTML emails that work
The problem with email is that each person you are trying to communicate with could have any number of hoops you have to jump through before your message will even reach them, or be readable when it does. If you want to send out graphically rich emails (and most people do these days), you need to allow for the way their email software renders HTML. Then there are spam filters to contend with – not only on the recipient’s PC, but also at the mail server level.There is no definitive list of things you can do to make sure every email you send will be seen by every subscriber, or that it will appear the way you intended when it does. This tipsheet deals with the most important issues that affect every newsletter you send.
HTML versus plain text
If you want your emails to appear with pictures and hidden clickable URLs, then you need to send HTML, but you should always send a simultaneous plain text version as well. A multipart email sent in this way can then be interpreted automatically by the recipient’s email client, such as Outlook Express. If the recipient sets their program to show all emails as plain text, they will see the plain text version you sent instead of loads of raw source code.
Styling your HTML email
Your website probably has some beautiful functionality – flash movies, JavaScript rollovers, expertly compiled cascading style sheets (CSS)… For your newsletter, forget all of that because it is useless. Well, except for CSS, which does work in non webmail clients (see below). If you include JavaScript in an email, or try to call a flash file, you are risking the email being rejected by ISPs’ servers and therefore being deleted rather than delivered. Your HTML email should be plain old HTML – but you can use styling. Also, don’t embed your pictures as attachments. Make sure you host them somewhere on a web server and call them remotely. It keeps the file size down. One other thing – don’t include an external stylesheet. All code must be embedded within the email.
Where CSS lets you down
CSS works in email, but there are variations on how it is handled. Generally, a classic HTML layout, with CSS code in the header, will render nicely on programs like Entourage, Outlook, Outlook Express. However, webmail systems like Hotmail and Yahoo mail are known to ignore the portion of email code, so if that’s where your CSS code sits, it won’t be rendered. Suddenly your beautiful email looks rubbish. To avoid this, put any CSS code into the area instead of the header. There’s another problem though, because tests on Google Mail (and Gmail) have shown that Gmail strips out all stylesheet information. This may change, but at the time of writing, any email sent to Gmail containing CSS code doesn’t render properly. The way round this is to instead use in-line styles – where you style the content from within the HTML tags. See the link at the bottom of the page for more information on this.
Content versus images
Don’t overuse images. An email with a very large image and very little text will trigger high anti-spam points. Make sure if you have only a little text that you also have a little picture, to be on the safe side. Having said that, if the large picture is the only thing giving you negative spam points, you will probably be OK.
How your email can be spam filtered
Your nicely coded HTML email may be just right for the email clients to display, but it could still be full of problems. Lots of red text, usage of spam-type words and loads of CAPITAL LETTERS will be marked as spam. The more spam-type elements you have in your email, the more points a spam filter will give it. If your points for any email reach the threshold set on the mail server, your email will be rejected. Many mail servers work on a score threshold of 5, but aggressive IT people may set a level as low as 3 – meaning you will not reach many people on that ISP if your email isn’t tested against a spam filter, like Spam Assassin.
When to send and how often
Other factors can affect your success rate. Send the email on a Friday evening and you may find you get less response than if you send it on a Sunday morning. Friday is when many people pack up for the weekend, and any emails they receive on Friday will be nudged down their inbox by Monday and may be ignored, whereas on Sunday, many people go online to shop or browse, and they are more likely to see the email and respond to it right away while they have time. The only way to get the timing right is to go on gut instinct and test your theories. Frequency and speed can also be an issue. If you broadcast your email to your whole database at once, you may find it hits too many AOL boxes too quickly and AOL’s filter temporarily bars you. A slower send rate may be advantageous – as well as making sure you don’t mail the same people too frequently.
Online tool for checking your HTML email against Spam Assassin’s spam filter
Practical guide to using in-line stylesheets
Newsletter Manager Best Practice Guidelines