Dashes vs Underscores in URLs
This is a pretty common question, and I talked about Dashes vs Underscores a few years ago (on an older blog of mine), so I believe it is a good time for an update as people are still asking about this.
Dashes vs Underscores:
Ok… So, dashes are interpreted by search engines (at least Google) as being a separator.
For example in a link we have sweet-apple-pie.
In this case, Google will see this as three different terms sweet, apple and pie.
If we use underscores instead of dashes and we have sweet_apple_pie, Google will see this as a single term. It ignores the underscores and it will take it as sweetapplepie.
So, you see, this is the main difference in dashes vs underscores.
When you are optimizing your permalinks, using dashes is a better choice when it comes to SEO.
Why is this happening?
I know, this sounds pretty weird so I’ll try to explain to you why this is happening.
It all comes from the starting times, when the internet was young and Google was a baby. The original technical engineers were programmers and they needed to find programming things (commands and such) which were usually based on underscore and they had to find them fast.
Why they didn’t fix this over the time?
Because in practical terms this doesn’t make that much of a difference. It is considered “a second order effect”. So the engineers prefer to work on much more important matters than this.
Anyway, Google does recommend the use of dashes instead of underscores, especially on fresh project. So we should listen to them.
I also recommend you to use dashes instead of underscores in permalinks on Blogspot because in time if you intend to migrate to a self hosted domain and WordPress, dashes will make your migration easier.
Another thing that you should keep in mind: don’t change your permalink after publishing an article (on any platform), unless you can set a 301 redirection.
I hope this answers your question regarding Dashes vs Underscores in permalinks.