Be careful with HTML Mail

Created on 2001-09-17 by Rainer Gerhards.

Newsletters nowadays tend to be formatted in HTML format. This allows nicely formatted messages, even including images. At the first look, it seems to be pretty cool. But it has its drawbacks.

If you try to have a broad reach, HTML is most probably not the format you will like to use. Here is a list of current problems with that formatting:

• Many companies block HTML mail at the mail gateway because of the security risks involved. You will probably loose part of your subscriber base because you'll never reach them. You might even not notice this problem, because many companies do not notify a sender of such a blocking mechanism. If you target corporate users, be very careful with HTML mail!
• Most cellular (mobile) phones can not display HTML mail. Thus the recipient will simply be unable to read it. Even WAP based mail services do often not support HTML mail.
• Most PDAs can not display it (correctly). Same problem as with the phones. Some PDAs will at least display some of the message content, but for sure it will not display nicely. For example, this is an issue with all Microsoft Pocket PC (CE) based devices prior to the Pocket PC 2002 operating system. The most prominent devices in this category are the Compaq iPAQs.
• HTML Mail requires more bandwidth. HTML mail is simply bigger. If you have a high-speed, low-cost Internet connection, this might not be a problem for you. But if you intend to reach people with low-speed (and probably high-cost) dial-up links, you'll loose subscribers if your messages become too large. Consider remote areas of the counter and - again - mobile users. They typically are able to transfer only a few kilobyte (KB) per second, so you 50 KB HTML newsletter will clearly have disadvantages compared to the same text-only newsletter only being 5 KB of size!
• Even desktop computers can not always display HTML mail! Sure, if you run the latest and greatest software releases, this is an unknown problem. But most people don't! There is an astonishing number of email clients out that are not capable of rendering HTML mail at all. In the best case, you message will look garbled. In the - not so uncommon - worst case, you message will simply be empty! We have also found, that a large number of Lotus Notes installations do not support HTML mail.
• Some people simply don't like it. That is a political argument. There are quite a lot of people out there that can perfectly process HTML based email. But the don't like it and will probably quit your list to get rid of it. Sure, if you can afford to loose all those subscribers, you can ignore this argument. But if you'd like to grow your subscriber base, you better care for them.

This list is far from being complete. So I highly recommend to at least embedding pure text message inside your HTML mail. This will at lease ease some of the problems (e.g. with some cell phones).

Another good alternative is to offer HTML format optionally. Then, let the user decide if he or she whishes to receive HTML or plain text messages.