I tried the search feature but did not see how to limit the search to this thread, so sorry if I am repeating another suggestion.
There are suggestions of bulk delivery - is there one for sending an email to all of the members of your guild? Lots of people don't bother with the GMOTD or the calendar.
Additionally, you might want to restrict the distribution by criteria:
* Only Level X - Y: Daily raid, PvP events, etc.
* By class ("need help gearing up a pally")
* By race ("naked gnome race this weekend")
* By prof ("need stuff DE'd")
* By guild rank ("'raiders', 'officer', etc.)
Naturally, this could get to be quite annoying, particularly in a large "enthusiastic" guild