This will give a count of how many entries are in each of the room's lists. UOPs and higher can get a count for a room.
/msg chanserv count #webchat
This command is primarily useful to get an idea of how many ops a room has or to see if the akick list is long enough to be worth considering reviewing. Actually listing people on the lists will fill your screen with information, while the count command is just a one line summary.