This is one of those Dilbert situations: if you read Wi-Fi Networking News via email and you're a Yahoo subscriber anywhere in the world, we have a problem: Okay, so I am aware that I can't notify you very easily that there's a problem when you receive these notes via email. But I just discovered via massive bounces from all Yahoo subscribers to the email version of Wi-Fi Networking News--the daily posts sent individually or as a collected digest each night--that Yahoo is using silent rejection on my email.
(Update: I was contacted by Yahoo, and they said they've tweaked their settings for my email server. Thanks!)
Despite using double opt-in methods of subscription and having received no complaints that I'm aware of from people trying to unsubscribe in the years of running the email distribution list for this site, Yahoo "deferred" every message sent to my double opted-in subscribers, did this for several days, and now has bounced all these messages.
As a matter of good Internet policy, all these subscribers accounts are now in suspension on my site to avoid any concern of sending mail after a mail server has said that the delivery has entirely failed.
Yahoo, like most large Internet companies, has little useful information about how to contact them when this kind of problem happens. If you have ideas (or work with or for Yahoo), let me or them know. In the meantime, I feel like a little part of my world has just disappeared!