This is more than you asked for, but here goes:
Emails sent by our web server look different than regular email sent from an email app. That's one reason they often land in spam folders. So, we use a "transactional email service" to send system-generated emails. These services are large, established, and Gmail, Hotmail, Comcast, etc. know who they are so the mail coming from them is less likely to land in a spam folder, or even worse, get blocked.
We use this service for order confirmations, customer service notifications, shipping notifications, classified ad inquiries... and forum notifications.
We switched to a new transactional email service yesterday, so that would explain the change in your inbox.
Yes, we do monitor email *we* send because we want to know if it was delivered and opened. Frankly, we don't care about that info as it relates to the forum but for obvious reasons, it's quite important for ecommerce communications. Knowing if our mail is being blocked or not opened can help us head off serious problems that have consequences. However, tracking is an all or nothing setting. If we track any email we have to track everything we send through that service provider. Regarding email from the forums, we do not save any of that data.
It should also go without saying that we have no way of tracking anything we don't send through that specific provider, nor can we see anything at all except whether it was sent, delivered, opened, or clicked. (We do save that info for ecommerce email.)
And that degree of tracking, from this service provider, would be what's flagging the email as "tracked" in your inbox.
Let me know if I didn't answer anything you have questions about.