There are many directories on the web. What makes dmoz more mportant is its autorityness and good relationship with many other web sites.

• Dmoz.org is very popular.

• It's free to submit.

• Once you submitted, you'llbe automaticly included many other web directories as well.

• It brings seo quality to your web site.

• Dmoz is open source.

• You Help to build the most comprehensive human-reviewed directory of the web

You need to be very very careful on submission to follow guidelines given by dmoz.org.
You can get more data about dmoz by clicking here ODP - Open Directory Project
thanks