An inbox is an electronic folder that holds new email messages.
Ex: Gary was about to send you an email with the details about tomorrow's sales meeting. Check your inbox, it should be there already.
Ex: I can't believe how much email they send me at work! I leave the office for just one afternoon, and the next morning I check my inbox and have more than fifty new messages!
Often email inboxes are divided into multiple folders. Usually, there is a special folder for spam, unwanted or unsolicited messages sent over the Internet to large numbers of users. Spam messages are typically used to advertise, to fraudulently obtain confidential information, or to spread viruses. When used as a verb, spam means to send one message to a large number of users.
Ex: Be careful not to download any attachments or click any links that appear in spam; someone might be trying to give you a virus or steal personal information.
A newsletter is a short publication sent regularly to members of an organization or group. The newsletter contains information that the group believes will be of interest to its members.
Ex: My friend Stephen's family is so big that they publish a quarterly newsletter on their group on Facebook. The newsletter helps people stay up-to-date on important news: who's starting a new job, who's expecting a baby, who's graduating from school, etc.
Ex: Every month, the company newsletter includes a bio of a different employee. Yesterday they interviewed Kevin, so his story will appear in next month's.
Newsletters can be print publications, but more and more frequently they are email publications. A LISTSERV is an application that can be used to distribute newsletters and other information to members of an organization. A listserv is essentially an electronic mailing list.
Ex: Molly subscribed to the theater's listserv so she could receive their newsletters every month. As a bonus, subscribers also receive special offers on tickets and invitations to special events.
Ex: Harry wants to unsubscribe from his university's alumni organization listserv. Although he likes getting its newsletters, recently he's been receiving a lot of spam.