Consider how it scales. Assume that at any given time, maybe 5% of your list are "on vacation".
Heh. This is a list for people who work at ISPs. In the 5 years I've been administrating this list we have had a problem with an autoresponder maybe once a year. For the most part, ISP folks just don't take vacation, and when they do take a vacation they usually read their email daily while on vacation. For those who take a vacation and use autoresponders, most people are very clueful about how they configure them.
jc
