Some mailing lists have low rates of traffic, . . .
Numerous incoming messages from various listservers or mailing lists by multiple users, require extensive system processing which can tie up valuable resources. Subscription to Interest Groups or Discussion Lists should be kept to a minimum and should not exceed what your disk quota can handle, or you for that matter. When you join a list, monitor the messages for a few days to get a feel for what common questions are asked, and what topics are deemed off-limits. This is commonly referred to as lurking. When you feel comfortable with the group, then start posting.