It's long been a thought of mine for some time that sidebars are too restrictive.
What I mean is that if you have a niche about, let's say Pets, and you are writing a post about Cats, but in the sidebar you have advertising material about every other animal that your niche contains.
Now wouldn't it make sense to only have Affiliate links to the actual post you are writing about?
So in the Cats post there would only be Links or Ads to do with cats.
Make sense to me.
With this in mind I have found a plugin that lets you create custom sidebars for each and every one of your posts. You can create an individual sidebar for as many posts/pages or even categories that you like.
If you are like me and you think this makes sense, the the plugin is "Easy Custom Sidebars".
No affiliation just helping out those want this option.