Email is certainly a form of communication without which most can't imagine being functional. There are tons of messages sent "to" and "from" us for our friends, family and business contacts. It can be quite time effective to turn around quick responses when it is needed, especially with business.
There are cases, however, when pressing the "send" button ignores a few rules.
When a part of a larger group, let's say 10 people, there is a type of trust with those (who are essentially strangers) on the list. The unstated rules are:
1. You will be respectful in any and all sent messages
2. If I make a request, you will oblige
3. My contact will not be given out to others without permission
4. No email will be cc'd to another person if it's uneccessary
Most of these don't need to be stated - they appear to be common sense. Even rule #3 can be a bit loose, especially when the other option is to give out phone contact information. Email is seen as a bit more neutral, especially for first contacts. Personally, there is a strong need to develop a relationship with those with whom I am speaking and so phone is preferred.
It is when we arrive at the fourth rule that there is really a lot of wiggle room and misunderstanding. No more is this evident than any groups one is a part where discussions are the main order of business. Everyone has an opionon and a strong need to share.
There are, however, limits.
When there are a larger number of folks on an email list back and forth conversations, limited to a few people, can be received quite negatively. When there is a target of any message, it is a good idea to limit the email to their inbox. We already receive a ton of emails, some unsolicited, any additional which are unhelpful or not needed will be met with aplomb.
Moreover, any negative messages or disagreements with a member of the group may not translate well over a digital medium. In such cases, the traditional phone (smart as it may be) might serve as a more effective means to reach out. Delivering negative messages and cc'ing anyone else should never be considered appropriate.