How much does punctuation affect on-page SEO?

[cgray01]

I have a page on a site that is targeted for "men's custom suits." Using the on-page analysis tool from SEOmoz it gives me an F for "mens custom suits" but an A with the apostrophe.

Even though the apostrophe is proper English grammar, does it affect rankings either way?

[Francisco_Meza]

I heard Matt Cutts talk about this in GWT youtube. He says that punctuation are looked at as spaces, with exception to the _.(underscore). So in this case, I think Google will try to match it close. For instance, I rank for the word Ship Car Overseas. I didn't optimize for the word Ship Auto Overseas, but I still rank for it. I also didn't optimize for the word Ship Vehicle Overseas, but I still rank for that too. My point is that mens and men's is closely related and that you will probably be fine either way.

[cgray01]

Okay, got it. That's what I figured, but SEO tools are limited to not take this variation into account, so I wasn't sure.