Digests collect a whole day's postings in one email.
The default delivery mode for most mailing list subscriptions is to copy you on each email sent to the list in near real-time, just a few seconds or minutes after it was delivered to the list server. This mode can be particularly useful if the list is time sensitive, such as with a news or financial information service, where immediate delivery is an advantage and gives you the option of reading the email right away or waiting till later if you wish. However, many discussion lists are less time-sensitive, and you might prefer to read a daily digest of all of the days postings in a single message. Most lists provide a digest option, and, together with filtering your lists , digests enable you to greatly reduce mailing list traffic volume and therefore usefully manage more lists than otherwise. Remember when replying to a posting in a digest that you will need to cut out the rest of the postings before and after the one you are replying to so you don't append the entire digest to your reply.