The serial positions are the first and last things in a list, and because of their positions, they are more easily remembered. Items in the first position have the primacy effect. The first item gets the benefit of long-term memory. The last items in a list are subject to the recency effect, where the items are stored in working memory. However, the recency effect can be diminished more quickly by distraction than the primacy effect.
Definition Source: UPoD

Source: UPoD

Primacy example: Some podcasts, like this episode from 99% Invisible, start with sponsor information right at the start so the sponsor enjoys the primacy effect.

Oh, this a cool one! As a podcast listener I appreciated your 99% invisible example. The chart helped me understand the concept better, but I would have appreciated an example in addition to that to drive the method home. Great job overall!
What I thought of when I saw your examples was my email inbox, I use Outlook for work and I could tell you what my first maybe three folders are … Inbox, Sent and deleted right? But what is at the bottom? I have no idea, I see RSS Subscription and Search Folders. I’m not even sure what those are! I have certainly never used them, I hope that serial position corresponds with importance in design applications.