Html mail gets broken by new lines
You cannot send email without line breaks.

The SMTP standard requires that lines be limited to 1000 characters. 998 really because the line must end with "\r\n".

If you successfully avoid having line breaks inserted for you, what will happen is that many email servers on the Internet will reject your email. Some will accept it, because they decided to ignore the standards. Guess who does that.

Many servers will not.

The correct answer to this problem is to create HTML email that has line breaks. This is really easy to do. Pick a few elements that occur fairly often, like &lt;/tr&gt; if you use tables, and CSS rule end braces, and put a newline after it.

Reviewing your HTML will also help you avoid very stupid looking HTML text, if you care. I was just viewing source on a newsletter email from TweakTown where they first include a bunch of CSS rules at the top. Then every single table row repeats the same CSS as inline styles. Really. Why? No wonder their lines are more than 1,000 characters long.

So, are people intentionally creating HTML with no line breaks to save space? Because if so, CSS rule spam is the opposite of saving space.