Hyphens or underscores in page names?

Hey all,

Is there any difference from an SEO standpoint between using a hyphen or an underscore in a page name?

For example: /page_name.html or /page-name.html

I'm wondering because the site structure is based on categories and subs, to keep page size down, while making the most of the site keywords, like so: /steel_beams.html, /oak_beams.html etc.

I have pages with PR values for the method I use (underscore) and they get indexed so should I get out more and assume there is no effect on SERPs either way?

TIA

Afaik search engines don't care if you use - or _, the main thing they care about are the keywords around them.

In a few sites I don't use either- I just run the words together, like so: pagename.php. That doesn't seem to have any ill effect- the major search engines can still pick out the individual words.

Thanks for you time and thoughts. Guess I'll stick to what I'm used to.

That's always the best approach! Of course, I'm talking about more than SEO...

From what I've found so far, SE's slightly prefer "-" to "_" BUT if you have pages that use underscores that are being indexed now, don't change them!!! The pages will be taken as new and have to fight their way back up again.

Really? I'd love to see the data/ source. I have found no difference.

As for not changing the page name, I agree.