In the past couple weeks a lot of the email spammers have been discovering their emails getting read less and less. Yahoo started a new email system of stopping more SPAM. I find it a little anoying because every email I send out now, I have to do a Captcha. But, if this is a short term thing and will eliminate SPAM, that I am all for it.
Mailchimp is one of those timely email SPAM senders. They specialize in timing the emails to be sent out at particular times of the day. SPAMMERS want to catch people as they are opening up their emails, rather than get buried by everyone else. Unfortunately, the timed emails have never been genuine, so they are a nuisance and best to be eliminated as much as possible.
I saw on Taskrabbit that someone was looking for help with Mailchimp. They said they were having a hard time with it and didn’t know why. The main reason Mailchimp struggles now is due to Yahoo. The other emails are supposed to still be SPAM friendly though. But if Yahoo is successful with doing away with more SPAM, it can certainly become more of an attractive email client.