It is good Netiquette to keep your address book private. Don't send invites to people in your address book.
Email addresses can easily be shared. They are valuable. If you have good friends, they are extremely valuable. Many sign up forms request access to personal email address books. They can automatically email your contacts with your permission.
There are often options to skip the sign up step for sending an email to contacts. The address is the contacts personal information. It is not polite to share personal information without permission.
Do not share personal email addresses without permission from the contact. Messages within social networks are more discretionary. Social networks provide public profile for viewing. There are privacy settings to control contact.
Keep address books private because many social networks ask to email contacts, which may annoy them.
Published on May 17, 2015 | 0:30 Seconds | Science and Technology
Personal Email Netiquette introduction. Keywords, graphics, and images.