The 7 deadly sins of eMail

Fellow IBMer Stefan tweets about a PC Welt article in German titled eMail madness - these are the worst sins in eMail. The article makes an interesting read (Google translate). What I found remarkable is that the author references basic communication theory in the beginning citing the four qualities any communication carries: factual content, relationship, self statement and plea. I learned about these qualities in the works of Schulz von Thun during communication training many years ago. Here are the 7 sins in summary:

1. Subject sin: The subject line is the one line advertisement of your eMail content. If it isn't related to your content or too general you and your receipients won't understand or later on find it. Subject and content need to match. Variations of this sin: pack too many information into one eMail (instead of separate topics), have a blank subject or recycle an old message with a totally unrelated subject line
2. Chain sin: Instead of summarizing the current status the receipent is left with sniffing through a whole chain of messages in the body field. The sin also carries the risk of information leaks: if you add new receipients to the chain they might gain access to information not inteded for them.
3. Ping Pong eMails sin: a rapid sequence of emails between 2 people (and a large audience in the CC list). eMail is inherently asynchronous. If a conversation is needed, the participants should use a phone or a chat client.
4. Avoidance sin: eMails are suitable for notifications and information. They make a poor tool for leadership and decision making - especially when there is dissent what the right course of action is. So using eMails to ask people to do unpleasant actions or announce decisions can be easily used to avoid responsibility, the responsibility to make decisions with the team and based on facts, evidence and leadership
5. Mobile Messaging sin: Using a mobile messaging client mostly cuts the participant off the mail chain, so (s)he might not be fully informed. Only really tough users would download and read any attachments. The (compared to a proper keyboard and regular screen) poor usability leads to very short context deprived eMails, stuff like: "go for it" or "Approved". They leave you wondering what this is all about
6. SMS sin: S stands for short, so don't try to communicate anything more complex than "the train is 30 min late" or "pls. call urgently regarding Project XYZ"
7. Useless guidelines sin: The intranet has eMail guidlines, but nobody cares since they follow the senior execs who are happy sinners. If you want things to change you need to be a role model

You could easily add a few more: the "endless long CC list" sin, the "reply with unchanged attachment" sin, the "everything comes with a return receipt sin" or the "you have to answer in 5 minutes expecation" sin. What are your favorite eMail sins?