Dear Colleagues: For nearly 25 years the categories mailing list has offered announcements, questions and answers about category theory, and sometimes general discussion. When the list started in March 1990 email was the only electronic means for quick, informal exchange. In the intervening decades the internet has evolved, and there are many other ways to present and discuss ideas. Forums like mathoverflow, personal blogs, and group blogs like n-category cafe are much better venues than a simple text mailing list. They offer formatting, tracking, permanence and search facilities. It is easy now to begin your own blog on wordpress or google blogspot. Until now, the categories list has sometimes posted lengthy back and forth exchanges. Your moderator has permitted that, at first since there was no other outlet, and later without thinking about alternatives. Such exchanges always lead to a number of subscribers leaving the list. Readers who might have been interested in our subject are driven away. Sometimes, as moderator, it has also been necessary for me to reject immoderate messages. Following some rejections I have been insulted, harrassed and occasionally threatened. Quietly taking that behaviour in stride for the good of the community was accepted as unpleasant, but necessary. Recently, another such incident has occurred, though fortunately mostly out of view of most of you. That has prompted my determination that the list needs its function expressed more precisely so that it can survive in the second decade of this century. Effective immediately, the categories mailing list will continue to post announcements of meetings, research, or other relevant matters, as well as questions about category theory and answers that are on subject and whose length is judged as reasonable by the moderator. As now, occasional off-topic posts may be forwarded without discussion. The list will no longer host lengthy exchanges. Announcement of venues where such exchanges are occurring may certainly be posted. Rather than a narrowing of mandate, the change should be understood positively as directing some types of discourse to more suitable forums. Best wishes, Bob Rosebrugh [For admin and other information see: http://www.mta.ca/~cat-dist/ ]