.com is the most preferable TLD most of the time, so many people choosing domain names have to pick between desiredname.something_else or totallydifferent.com.

From wikipedia:

The biz TLD was created to relieve some of the demand for domain names in the com top-level domain, and to provide an alternative for businesses whose preferred domain name in com had already been registered by another party.

.org at least implies an organization, whereas .com is the most generic 'commercial'. But .biz seems like a total duplicate that doesn't seem in widespread use <pun>and deserves to be closed. </pun>. Does .biz have any advantages over .com? Are .biz domains worth registering if .com is already taken?