From the article:

  Some prerequisites to using this information:
  * You must be sending HTML, not text, emails.

Compare and contrast with the complaints here about HTML email:

http://news.ycombinator.com/item?id=1500488

Here is a direct link to web2.0 Expo's last html email campaign http://recp.mkt41.net/servlet/MailView?m=35580090&r=NTUy... (link is a little long)

It's not spammy but it does include graphics, colors, layouts, etc. Also I could be wrong but I think using an html email gives you a more accurate open rate.

Sure some people can misuse html email's but I don't think they are all bad.