Why does unsubscribing from a newsletter take “a few days”?
I work for a company in a department that sends out on average, 2 million emails a day.  These are emails to people who (1 or more):- have signed up and are receiving a verification email.- are giving us money- are using our site at least once a week during the first month, and even if they taper off, are at least using it every 180 days.So, we're not sending email to people who we've never met, as it were.  We have an unsubscribe link in all our emails, and an account email settings page that has about half the mailings we can send as initially subscribed (we like money), but which can be turned off.  We even have links to our settings page in the emails and on all the site pages.I like to think we're being fairly responsible, all in all.Like I said, we send 2 million emails a day.  That goes out on a lot of machines, and we have lots of automation going on nearly every minute, and lots of email queues being prepopulated to send out in volumes acceptable to gmail, outlook, yahoo, etc.So, you've asked to unsubscribe to the email you received last week.  We got you, fam.  I analyzed logs and did some live testing using our VPN at offices across the world.  Over the past 3 years, you've been removed from your chosen lists within 2 seconds of clicking the button.  This obviously doesn't cover hardware/network/server problems.So we're cool, right?  Nope.  You're unsubscribed all right.  However, we already placed you in the queue for our most recent mailing about 4 hours ago, and you're going to get the last one from us anywhere within 2 seconds from now to maybe late tomorrow.You really won't get anymore from us after that, though.