Sometimes it's spam, sometimes it isn't

Like most people, I get lots of email from merchants I’ve done business with online. Sometimes the mail is legit – purchase confirmations, shipment notifications, etc. Sometimes it isn’t – this week’s big sale, new product announcements, “partner” emails, etc. Will using the Train as Spam and Train as Good commands teach SpamSieve to differentiate between various types of mail from the same sender, or must it be either all Spam or all Good from each source?

Thanks.

It’s best if you can unsubscribe from the merchant’s e-mail list. There’s usually a way to do this so that you only receive e-mails related to your orders.

Yes, you can do that, and it will probably work OK, but it’s probably not necessary. I would only do this as a last resort because you would almost be lying to SpamSieve, which could have consequences for the overall accuracy. If the unwanted messages have a specific format, you could create a regular Mail rule (above the SpamSieve rule) to get rid of them before SpamSieve sees them.