In terms of SEO, what's the difference between:
I could not find anything useful regarding this concept, can you explain this?
Back in the days the trailing slash suggested "this is a directory" in contrary to "this is a file". Browsers would react slightly faster – or at least that's what I was told – when they were indirectly told "look for a file called index…". Today that trailing slash is next to obsolete.
Today it is considered good practice to either always or never have that trailing slash – otherwise it could be considered duplicate content.
But as far as I know neither theory has any impact on SEO.
Update: for what it's worth I just checked the google webmaster tools support pages about Duplicate content and indeed they have the following recommendation that adresses also the trailing slash issue:
According to Google , they will treat URLs with and without a trailing
/ as different documents:
Historically, it’s common for URLs with a trailing slash to indicate a directory, and those without a trailing slash to denote a file:
http://example.com/foo/ (with trailing slash, conventionally a directory)
http://example.com/foo (without trailing slash, conventionally a file)
But they certainly don’t have to. Google treats each URL above separately (and equally) regardless of whether it’s a file or a directory, or it contains a trailing slash or it doesn’t contain a trailing slash.
Different content on / and no-/ URLs okay for Google, often less ideal for users
Emphasis is Google's not mine.
Now servers may technically handle these URLs differently but the recommendation is that they all be equivalent. Google seems to follow this advice as well.
Serving up the same content on two different URLs can be confusing - for users and search engines, so they recommend against it and provide instructions about normalizing your URLs.
If you follow the remarks of various Google employee's about SEO and SERPs, you will find a common theme:
Google does everything it can to improve the user experience.
So for SEO, you should be canonicalizing your URLs to assure a consistent user experience.
It merely indicates that the location points to a directory and not a specific file. The webserver will then show the default page for that directory if one has been set up or otherwise list the files in that directory.
It has no SEO meaning or value. (Although being able to pull up the index page of that directory via two URLs can result in duplicate content which has SEO implications).
When I choose between using a trailing slash or not, most of the time no trailing slash looks cleaner. However, I ran across one interesting case in which having a trailing slash can help with search engine optimization (SEO). That is the case that your document has what appears to be a file extension that is not
.html. This becomes an issue with sites that are rating websites. They might choose between these two urls:
In such a case, I would choose the one with the trailing slash. That is because the
.com extension is an extension for Windows executable command files. Search engines and virus checkers often dislike URLs that appear that they may contain malware distributed through such mechanisms. The trailing slash seems to mitigate any concerns, allowing the page to rank in search engines and get by virus checkers.
If your URLs have no
. in the file portion, then I would recommend omitting the trailing slash for simplicity.