Underscores vs. dashes in URLs


MATT CUTTS: Hi, everybody. I wanted to give you an
update on underscores versus dashes in URLs. This is something that a lot of
people have asked me about. And I had talked about
it a long time ago. And so I figured it was
time for an update. So first, let me give a little
bit of history about why, whenever we see an underscore,
we join that in the URL rather than separate using that. So what I mean? Well, if you say red dash widget
in a URL, we view that dash as a separator. So we index the word red, and
we index the word widget. And those are separate. Whereas if you were to have War
of 1812 with underscores– so, war of 1812– instead of separating on the
underscores we actually glom all those together. So that’s one term that you
could find by searching for war underscore of
underscore 1812. Seems kind of weird. So why does Google
do it that way? Well, whenever we started,
AltaVista was huge. We were just this little
tiny company. And we were all very techie. Lots of computer programmers. And we wanted to find exactly
what we wanted as far as terms. We really cared
about precision. And so whenever you are a
programmer, you often have things like, if you’re a
C programmer, you might recognize TMP underscore MAX. And so, if you are a programmer,
you want to be able to search for that term and
find TMP underscore MAX– and that exact term. Not just TMP and MAX that happen
to be on the page. So it was because the original
engineers were programmers, and the programmers wanted
to be able to search for programming terms, that we
joined based on the underscore rather than having that
act as a separator. Now in practical terms, it
doesn’t make that much of a difference. It’s kind of what we call
a second order effect. It’s not a primary thing that
really makes a huge difference. For example, Wikipedia has a
lot of pages that say war underscore of underscore 1812. That doesn’t keep Wikipedia
from ranking. Because there’s page
rank, there’s proximity, there’s title. There’s all the other signals
that we use, over 200 of them. But if you are going
to make a site and you’re starting fresh– so you’ve got a blank
slate to work with– I would probably go ahead
and go with dashes. And I would continue to go with
dashes at least for the foreseeable future. We had thought about doing a
little project to split on underscores a few years ago. But it turns out the amount of
impact it has in our rankings is relatively low. And it turns out, to get
engineers to do that versus some other projects– there were other higher impact
projects that we could have them work on. So at least for the time being,
we still join on the underscore and separate
on the dash. So a few people had asked, you
were thinking about splitting on the underscore, do
you do that yet? The answer is no. I don’t know when we will. Nobody is slated to be
working on that. So at least for the time being,
it’s better to stick with a dash. Now if you already have a
website, if it already uses underscores, and if it already
works the way you want, don’t go back and rewrite
every single URL. I would only bother when it’s
a brand new website, when you’re really working
on something fresh. When you’re trying to say to
yourself, OK, I can do this anyway I want, then that’s
a pretty good time to go for dashes. If you’ve already made the
choice and you happen to use underscores, I really wouldn’t
worry about it that much. It’s not a huge factor. But I just wanted to explain a
little bit about the kinds of reasons why we would do that
in the first place and just give a little bit of context
and a little bit of update. So I hope that explains things
a little bit better. Thanks everybody.

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