Posting of a single item to multiple topics around The WELL is considered impolite, especially when done within a single conference. Within any given conference, it pays to keep in mind that anyone who may be interested in your comment is likely to be reading most of the topics where you might post it. So, posting it once should be enough. If you aren't sure which topic would be most appropriate, feel free to ask the conference hosts where they think would be best. If you'd like to start a linked topic, ask the conference hosts.
Hosts are there to help.
Ask for it. Conference Hosts Conferences on The WELL are each tended by one or more hosts. These volunteers may, in the community interest, delete a comment. However, they may not edit it. Start a topic to discuss the deletion publicly.