Wie gehen Sie mit Email-Bounces um? Kennen Sie den Unterschied zwischen Soft- und Hard-Bounces?

You will always have some invalids due to people changing email addresses, but the lower the number, the better your reputation. A majority of spammers (if not all) don't care about bounces and tend to use the "spray and pray" method. Spray and pray is when a spammer fires out tons of email (usually in long bursts) without aiming, hoping that someone will buy from them when they hit a valid account out of the millions they harvest off the Internet. They never stick around to collect bounces to clean their lists and usually move on to the next rock they can hide under to spray and pray again. So every time they send, they are sending to the same valid and invalid addresses. This is why removing dead addresses is vitally important the first time an ISP tells you the address you're trying to deliver to is no longer valid.