How do paging works on blogs? What kind of script/code is it using?

I am wondering how blogs, online journals, xangas etc. know how to display certain number of entries/articles on one page. For example, on WordPress, you can set to show 10 articles/entries per page.

What kind of script/code(s) make that happen?

What’s such "function" call?
Hi Ray:

Any WordPress blogs, such as JohnCow.com, JohnChow.com, eMonetized.com, etc.

As for Xanga, I don’t know any on the top of my head right now. >_<