WordPress registration process. (Back-end)

Hello,

I am doing some website statistical analysis, and I am in need of some explanation as to how wordpress manages its registration process.

Basically I have god up to a point.
I am looking to know how wordpress distinguishes between an Activated user accound and a non-activated user account.

The reason is that I need to identify how many users are actually activating their membership.

In the wordpress Admin area, the number of total users is completely different from the number of users in the wp_users table.

My guess is that wordpress only count all users who have activated their accounts. But please correct me if I am wrong.

Any help with the above will be greatly appreciated!