[thelist] Spam filters

[Shawn K. Quinn]

On Tuesday 14 September 2004 08:33, Jason Handby wrote:
> I have been working on a website which allows people to register and
> then search a database according to various criteria. Once the user
> has finished searching, the site emails them a detailed report on
> their search results that they can refer back to. This email is
> formatted as HTML.

Is there a compelling reason to do so? Is there any content that cannot 
be conveyed in plain text? (My guess: probably not.)

> Recently the client has noticed that they are having more problems
> with emails being blocked by users SPAM filters and not getting
> through. We know that the email is not SPAM, but clearly it looks
> like SPAM as far as (at least some) filters are concerned.

If it's in HTML, generally it will be assumed to be spam or scored at, 
say, 50% of the threshold. I trashcan anything with an HTML part by 
default and only whitelist it or fish it out of the trash if I can 
identify the sender as someone I know I want to hear from. This catches 
100% of wormspew messages and my friends have figured out how to send 
e-mail in plain text only (I even drop multipart/alternative with a 
text/html part, as I figure if it can be said in plain text, why does 
it need to have an HTML version as well?).

Also note, my e-mail client does not render HTML by default for security 
reasons. It can if I specifically ask for it (which I never really have 
a need for).

> Do any of you have any general suggestions / guiding principles for
> creating emails that don't look like SPAM?

Don't use HTML in e-mail unless you cannot convey the same content any 
other way. If you must use HTML, consider just giving a URL back to the 
results in HTML on the server, rather than sticking the HTML in an 
e-mail.

> Are HTML emails more likely to cause problems than plain-text ones?

Definitely.

> Does the length of the email matter? Are there any key phrases we
> should be avoiding? (We're not selling Viagra :-) )

I can't think of any, besides fairly obvious ones (and I hope I don't 
need to list them).

-- 
Shawn K. Quinn