You have that awesome blog. You are very happy with how it looks and your content creation is on fire. And then a person wanders through search or link somewhere in and out of one of your older blog posts, never checking other posts.
There are many reasons why they aren't staying around. Your blog post wasn't impressive enough or they didn't like the way the site looks. Perhaps the loading time was too long for them (people are very ADD with loading times these days) or the post didn't give the information they were looking for.
There are other reasons too: Your blog is missing some ways to tell the new reader where they can find more content like the one they have just found. They think this was it, there's nothing more to see.
At the same time this person may be lost in your blog. They don't have a clue that they are in an old blog post or they don't know how to get to read more.
On many mobile sites several links seem to be missing. Or they are so well hidden you give up trying to find them after a while.
Always make sure there's an easy way to get to the front page of the blog, at least. This way the person coming through search to your old post can find the new stuff as well.
Front page link also helps when a person feels lost in your blog. You are showing them a way to get "home".
I keep seeing some WordPress blogs without dates and times added on the blog posts. Okay, the time isn't necessary, but the date is.
It's not enough that the date is present in the url of the blog post. It must be there in the post as well. On the top or on the bottom.
There are a couple of reasons why the date must be there:
1: Your reader wants to know when this was written. Some of the information provided may not be relevant anymore. Also if you mention you'll going to follow up soon it's easier to dig up the follow ups if you know when the original post was written.
2: Your reader may be reading the post with other device than their laptop or desktop. Smartphones have very limited screen sizes and therefore also the address bar is narrow. Checking the date from the address may prove to be difficult.
I have been googling information of market hair dyes a lot lately. I've been wanting to see the results of those who have tried a dye I'm interested about. Some of the blog posts have been about how someone just bought the dye and is going to test it later. At this point I'd like to be able to see if there's a post written in next few weeks with the results. If there's no archive to find it from, it can be impossible to dig it up.
I know, someone has told you how you are cluttering your sidebar with useless stuff like archives. Archives aren't completely useless, especially if they are sensible and well organized.
When a new reader comes to your blog through an old post they may want to see if you told more about the subject in later posts. When they know the date of your blog they can easily see from your archives if you have actually wrote something more about the subject in a short period since the original post.
The next and previous post links are good too, but finding a certain post through them can be quite numbing task. Similar posts can also help at this point, but it's not the best solution either. Blog's own search helps too but may not be refined enough for this.
Categories let your readers easily to find more about the same subject. Perhaps you write tips on how to become more successful Etsy seller. But you also write about other subjects.
When the reader comes to your blog through one of those posts about said subject they may want to see your other advice about it as well. Categories are an easy way to collect all that information in a same place for easy read through.