Through client work, and "show of hands" exercises at several recent presentations, I know many associations apply very conservative limits to their regular all-member communications. Monthly appears to be a common, acceptable frequency. Unfortunately, math is not in our favor. This means for someone receiving 100 emails per weekday, they have a 0.05% chance of seeing your carefully-constructed e-newsletter, all other things being equal.
In this context, it was interesting to contrast this under-communication scenario with listserv feedback from vendors/experts regarding "How many emails do you send for each event?" To quote two: "sending reminders one week, one day and one hour in advance .." and "for Associations with engaged members: 10 'marketing' messages per event Associations with wider, less engaged audience: up to 20 'marketing' messages per event."
This is great to maximize participation in a single event, but it might mean sending more emails for that event than you do all year for the association at large! And if you have multiple events, your 'regular' communications might dwindle to only 5% or 10% of the total messages you send. On the bright side, your odds of being read by the typical member/customer might rise as high to 1 in 100. On the down side, the content map for your e-communications might show a mix that's 5-10% substantive industry news, 5-10% housekeeping/transactional stuff, and 80-90% promotional content ... probably not the mix you had in mind. Depending on how you monitor member communications, you may not even be aware of it and the signal it sends to your audience.
The core messages you want to convey and the value you need to impart through your e-newsletter may be swamped by other, simpler messages that may collectively convey the impression that the organization 'exists primarily to sell you stuff' (to quote Scott) rather than provide pertinent information, educate, and support them and their industry/profession. -Kevin