SEO Tip #17: Should I use underscores or hyphens in URLs?
Matt Cutts: It does make a difference. I would go with dashes or hyphens if you can. If you have underscores and things are working fine for you I wouldn’t worry about changing your architecture.
A while ago I said we were looking at underscores as separators and the reason we typically never talk about stuff in the future is that gives us the freedom to change our mind. In fact the people who were working on that project worked on something slightly different from underscoring in the url that was actually higher impact and a much higher win, we might still get around to that so thanks for the ping.
I might ask somebody on our quality triage team if we can take a fresh look at this, but for the time being hyphens or dashes are treated as separators and underscores are not. That might change in the future but that’s the way it stands right now.
About the Author
Andy Johnson has been on the Internet since the its dawn(ie his first computer program was recorded on cassette tape) and his first hard drive cost about as much his current MacBook. His first byline was in 1993 for a local newspaper rag he eventually helmed, and his last “real job” was at a computer start up which ended when it ended. Throughout it all he’s freelanced and blogged. Now he is mesmerized by Search Engine Optimization forever trying to “rise to the top” for the right reasons. He’s been married to his wife Julia for as long as he can remember and has two lovely, wonderful children. He looks forward to sharing the latest in the technical best for all the online entrepreneurs.