Outbound mail now runs through Amazon SES in the Frankfurt region, and leaves from your own address instead of one of ours.
You register your domain in the mail settings and get back the DNS records to add: three CNAME records for the DKIM signature, a custom return path for notifications about undeliverable mail, and a verification record generated per registration. All three have to check out before anything can be sent, and a domain can be active for one account at a time.
Every account gets its own separated sending space with its own suppression list. Bounces and spam complaints arrive in real time: a hard bounce and a complaint suppress the address, a soft bounce does not. You can view that list, with the reason each address is on it.