I recently started a directory on a domain i wasnt using.
When people add their site they are asked to link back to me but its not required. I want to keep my directory for the people who use it, i don't plan on charging for adding a site and i dont want to force people to link back to me if they dont want to.
So what im wondering is will the amount of outbound links do me favours or would it really be worth insisting on a backlink?
Comppared to backlinks, how effective are outbound links to the site that hosts them?

Also, i wrote a mod that displpays the last referrer in the footer of everypage.
Im hoping that if people have their link displayed in the footer of every page they might be more inclined to link back.

Comppared to backlinks, how effective are outbound links to the site that hosts them?

They are 0% as effective as backlinks.

but the anchor text is also copy for the page the links are on

Well getting lots of incoming links is all ways good to have but just forcing them to link to you will have a bad impression on your directory rather than that make the directory paid and invest some money in building some links and advertising.

Akash

every links are important

In terms of SERPs it does matter.

Akash