While some signatures are formatted to look interesting, a signature longer than 3 or 4 lines starts to waste space. It is generally a good idea to read a few messages before posting or replying. Every list has a unique culture, and you should be aware of it before you become a part of it. The digest period varies from list to list, depending on list activity. A busy list might be digested daily.
All messages distributed by thelist are also copied to thelist-d.
When the digest time is up, the digest of all messages since the last digest is distributed. Subscribe to the digest by sending mail to the -request address for the digest. While the digest list in theory can have an archive, in practice the archive is maintained at the main list. Messages are bundled together weekl and stored for retrieval. You can subscribe when you return, and catch up on messages by retrieving the weekly digests.