On Thu, Mar 3, 2011 at 7:42 AM, Eckard, Steve - eckardsl <[log in to unmask]> wrote, in part:

Greetings, all. I have a new owner of a list which is an announce only list used very little, but has over 49000 subscribers. Mostly these have been the result, I believe, of someone putting a link on the website for the organization which makes it so easy to request subscription. Fortunately being an announce only list is not as easily compromised as an open. My question is how can this owner determine which of these subscribers are still active/valid? Would sending a message to the list result in delivery errors and deletion of unavailable accounts?