>Hi there, the application I am working on needs to send reports/letters to customers via email. We are wondering whether to send them in HTML or PDF format - what are the advantages and disadvantes of one over the other.
>
There are tons of issues here, as you no doubt gather from the other responses. Let me add a few thoughts.

First, a big issue is what your customer base looks like and what control you have over them. Will they all have a PDF reader available? Do they all have modern email clients that can display HTML messages? If so, is it always Outlook? Even if they theoretically could display HTML, some people actually turn this feature off in Outlook due to fear of active content, etc.

So, you might conclude that you need to be able to supply PDF to some customers, even if HTML would be preferred. If so, look closely into what product you might use to generate these files. Adobe's PDF Writer is specifically not licensed for server-based operation. Adobe supposedly does offer a server-based approach using Distiller, but I'm unaware of the licensing issues/costs. Other 3rd party products include Amyuni and ActivePDF. Alot of Web Connection developers use Amyuni, but I cannot say that there is uniform success reported with any product yet.

If you opt for a pure HTML approach, depending on security issues, you could get around some of the mail client issues in a few ways, including attaching the HTML file, or even publishing a copy to a web server and providing a URL to it. But all in all, you might conclude that a sufficiently high percentage of your users can display HTML mail messages that this is a viable solution. HTML is much faster to produce than PDF files, and the email message sizes should be much smaller, thus reducing various loads on your overall system/network/connection.

If you do go the HTML route, I would suggest publishing any graphics on your own web server, and including <img> tags with abosulte HREF values, rather than attempting to embed the graphics in your mail messages. Outlook does support the latter, using multipart messages and some manner of referring to the other message parts in the HTML, but this is not universally supported by other mail clients that can otherwise display HTML messages.

Randy