If you have an older email list that you have not sent a campaign to, including them again after a long break could result in spam flags as people are surprised (or worse, forgotten you) to hear from you again.
A gentler way is to use a feature called "Hide Show" to display a message just to that list. Then add [unsubscribe] (including the parentheses) as the link on text to allow them to leave.
A client recently sent a campaign about an upcoming show. All lists saw the main content (click to enlarge):

But the older list also saw this message (hidden from the other lists) (click to enlarge):

Letting them unsubscribe encourages a gentle leave rather than a spam flag, which no one wants.
The Result?
- 6 unsubscribes
- Zero spam flags
So if you have news/promo/image that you only want to show to a specific list, go ahead and try it. Select the news items block then to the left are your options.
Have fun!
