Why is washingtonpost.com not cached in Google?

[ppzhao]

Why isn't example.com cached in Google? Even the pages that don't change frequently, such as http://www.example.com/wp-dyn/content/blue/widgets/?nav=left

I the pages in example.com is getting some rankings, and instead of the snipet of text, it posts the title and description tags in Google SERPs. Even though Google isn't caching those pages, does that mean Google doesn't know anything about what's on those pages except for the Title and Meta tags? Or does it mean Google knows what's on those pages (such as keyword focused content, keywords in h1 tags, etc), but is just hiding the cached version from users because of some kind of "no cache request" from example.com's programming?

Thanks,
Paul.

[edited by: ThomasB at 4:50 pm (utc) on April 10, 2006]
[edit reason] examplified [/edit]

[LifeinAsia]

Because you have to be a registered user to view the articles (at least the articles that I checked).

[ppzhao]

I understand that the articles are protected, but what about the Classified pages that you don't have to register for?
Example: [washingtonpost.com...]