The Multipart/Alternative MIME Format

The most important thing you need to know about HTML email is that you can't just attach an HTML file and a bunch of images to a message and hit "send." Most of the time, your recipients' email applications will break all the paths to your image files (because they'll move your images into temporary folders on your hard drive). And you can't just paste all your code into your email application, either. Most email apps send messages in "plain-text" format by default, so the HTML won't render. Your recipients would just see all that raw source code, instead of the pretty email it's supposed to render.

You need to send HTML email from your server in "Multipart-Alternative MIME format." Basically, that means your mail transfer agent bundles your HTML code, PLUS a plain-text version of the message, together into one email. That way, if a recipient can't view your beautiful HTML email, the good-old-fashioned plain-text version of your message is auto-magically displayed. It's kind of a nerdy gobbled-geek thing, which is why a lot of people mess things up when they try to send HTML email themselves. You either need to program a script to send email in multipart/alternative MIME format, or just use an outside vendor (like euro.message LIVE) to deliver things for you.

Image Files in HTML Email

Embedding images and photos into messages is the number one reason people want to send HTML email. The proper way to handle images in HTML email is to host them on a web server, then "pull them in" to your HTML email, using "absolute paths" in your code. Basically, you can't send the graphics along with your message. You host the graphics on a web server, and then the code in your HTML email downloads them whenever the message is opened.

Incidentally, this is how "open tracking" works. You place a tiny, invisible graphic into the email, and then track when it's downloaded. This is why open tracking only works in HTML email, not plain-text, and why the new email applications that block images by default (to protect your privacy) can screw up your open rate stats.

Free Hosting Services

When it comes to hosting the images for your HTML email, you really need your own server to do it. Don't try hosting images on a free "image hosting service," because those websites often put scripts in place to prevent you from linking to them in emails (they can't handle all the traffic). And since you really do get what you pay for, free image hosting services tend to be pretty unreliable under heavy traffic conditions. Also, spammers use free image hosting services all the time, to "cover their tracks." If you don't want to look like a spammer, use your own web server. If you use an email marketing service (like euro.message) they usually come with a newsletter builder tool with image hosting capabilities built-in.

Delivering HTML Email

Many newbies make the mistake of setting up forwarding lists, or "CC'ing" copies of a message to all their customers. This causes all sorts of problems, like when a customer hits, "reply to all." Plus, there's no way to do any kind of individual tracking or personalization when they CC: a big group like that. Finally, it just looks so unprofessional and impersonal when recipients can see your entire list of other recipients like that.

That's why when an email marketing system (like euro.message LIVE) sends your campaign, we take your message and send it one at a time to each recipient on your list (really, really fast). Unlike your work computer linked to your local ISP (which probably has a standard monthly bandwidth limit), email marketing vendors like us use dedicated mail servers that are capable of sending hundreds of thousands of emails (even millions, for larger vendors) per hour.

Other factors you should consider when delivering HTML email campaigns:

• If you send from your own server, your ISP may throttle your outgoing emails or shut your account down, if you send too much too fast (like more than 500 per hour). They may also shut you down if you exceed your monthly bandwidth limit. If you've ever sent an email campaign to a big list of recipients, and you attached a giant PDF, this has probably happened to you before.
• Email firewalls and ISPs who receive your emails don't like receiving tons of emails from one single IP address at once (unless they normally receive tons of emails from that IP). So if you only send occasional email campaigns from your IP, you may want to throttle your delivery, or spread them across multiple IPs, to avoid accidental blocking. Email marketing services usually split your campaign up into pieces and send it out over lots of different IP addresses.
• If you send emails from your desktop email program, chances are you're connecting through your local ISP. If you don't have a dedicated IP address setup with your ISP, you're probably sending emails from a dynamic IP address. ISPs and spam filters don't like receiving lots of emails from a dynamic IP address, because it looks like a hijacked home computer. You should always send from a dedicated IP address, or use an email marketing vendor (like euro.message LIVE).