Difference between format of good and bad e-mail

In e-mails format play a vital role to make it good or bad. Following are the points on differentiation between format of good and bad e-mail:

Subject line:

Good e-mail always has an accurate subject line. Subject line is like a headline of news. In good e-mail we can know about the inner matter of e-mail by viewing its subject line. Subject line is always short and has a suitable word for whole e-mail. For example: subject: 9 am meeting postponed. From this subject line reader can easily know about which meeting we are talking about in e-mail.

Bad e-mail does not have a suitable subject. E-mails that do not have subject, these also consider as bad e-mail. Moreover, in bad e-mail subject line is long and have confusing subject. For example: subject: meeting. From this receiver or reader cannot know about which meeting we are talking about.

Message:  

In good e-mail message starts with greetings like dear and then name of receiver and if you are writing your e-mail to company not to a single person then you may write “To whom it may concern”. After this, good e-mail has first loaded message i.e. it has purpose of e-mail in his first sentence. After that, there is closing remarks in good e-mail i.e. to thanks reader for spending time to read our e-mail and then information about contacting to us if have any question. Then after, there is closing like best regards, sincerely etc.
In bad e-mail the main purpose of e-mail is buried between unimportant sentences. There is no any greetings and closing in message. This type of e-mail is look like wastage of time that’s why receiver not read it.

References:
http://www.mindtools.com/CommSkll/EmailCommunication.htm
https://www.englishtown.com/community/channels/article.aspx?articlename=184-email
http://www.youtube.com/watch?v=jiaJbKPhAFk