when is SSL necessary?

I have a section of my website that is password protected. The section contains confidential info - would this warrant setting up SSL as well? I know it's typically used when users are submitting personal info (ss#, credit card etc) however, users won't be submitting any info on this site.

thanks!

that data is still transferred back to the user when they login.. so just because it's not being transferred to the server as a user submission, the data is still being transferred from the server to the user unsecurely.. so yes a SSL certificate is definitely warranted.