What's the SEO impact of url suffixes?

[Cornucopia]

Is there an advantage/disadvantage to adding an .html suffix to urls in a CMS like WordPress. Plugins exist to do it, but it seems better for the user to leave it off. What do search engines prefer?

[RyanKent]

When possible, always remove the .html or any technology suffix such as .php, .htm, etc. A few reasons:

• this information offers no value to users nor search engines

• it needlessly increases the length of your URL

• it offers hackers an additional piece of information about your web server files. You want to make the bad guys work as hard as possible

• it helps a lot with SEO when you change technologies. There is good reason for .html pages to move to .php pages. When that change is made, all the pages on a site need to be 301'd. The entire process is a big waste of link juice for the entire site which could be avoided if the technology extension did not exist. While .html and .php pages are common today, next year .seo pages might be the popular extension.

[dumperama]

There are actually some studies that can be found on the internet that suggest that the CTR correlates with the extension shown on the SERP, namely .html is supposedly having a positive impact on the CTR of up to 200%.

I was trying hard to find the website I read it on, but on the quick I couldn't find it. It contained a "study" on it with eyetracking and it made sense.

I've personally never run a test on it, but I decided to add html to our documents by means of Mod Rewrite.

As far as search engines are concerned, it does not matter at all. But overall, the visitor should be more important and seeing that it does not negatively impact rankings, it's worth a try.

[RyanKent]

I would love to see the study if you can find the link later. I agree sometimes study results conflict with prior conceptions and I have been mistaken before, but those study results really sound counter intuitive.

[dumperama]

After I finished work, I will dig through my history and can hopefully deliver.

Update: I spent 1 hour going through my browser history and I was not able to find it. Kinda freaks me out. Sorry.