Should I strip file extensions from my URLs?

Matt's answer:

CUTTS: Tons of questions from the UK. J, from London, asks, “Does stripping file extensions from URLs–,” so instead of page.html, just having page “–have a demonstrable benefit in the SERPs?” I don’t really think it does. And personally, I would not do that. People like to know that it’s an HTML page that they’re hitting. If you have a directory, then sure, have the directory. But personally, if you don’t have “.html” or if you’re–then if your web server’s not configured correctly, we’re making guesses about is that a PDF or is that a “.exe” or is it a CFM, and you know, all the different types, mime types that there are trying to figure out what type of content it is. So if possible, I would probably just stick with this standard convention, have something HTM or HTML. Users understand that. They don’t get confused. They won’t be quite as cautious about clicking on a result. So, you know, it doesn’t make that much difference in core ranking, but I think behaviorally and, you know, not making something that’s a rough edge that people–they get stuck on or worry about. I would probably stick with having the extension, having “.html” or something like that.

by Matt Cutts - Google's Head of Search Quality Team

Original video: