A quick note on cross posting. It can be really confusing. Some announcements are and should be routinely sent to all the lists (gig list, etc.). Basic threads don't need to be cross-posted and PLEASE DO NOT REPLY TO A POST ON MORE THAN ONE LIST. People just don't know what is going on. If something is really interesting, check with the author and see if he minds being quoted on another list and "re-introduce" it as a new thread. This keeps the replies from bouncing and getting CONFUSING. Confusion is the main issue.
I subscribe to 3 lists myself and enjoy them all. Most topics on the other lists are appropriate for harp-l, but don't always "need" to be on harp-l. Some topics appear regularly on all the lists. It just depends. Usually, there is no need to prod these things along. So, it is really best to try to separate out the traffic from different lists.
CC's One interesting note. Sometimes folks send something to one or both lists as well as an individual and "cc:" the list itself. That tends to screw-up peoples mail folders sometimes ;-). Try to remember to include harp-l's address on the "to:" line always. Have fun and enjoy the diversity!