"No SSL" means the site doesn't use encryption at all (if you try to go to https://thenameofthesite you won't get anything). Most sites on the Internet don't use SSL because they don't need to--they don't accept credit card information, for instance.
For example, my site at xeromag.com would sho up as "no SSL" because there's no security certificate there--I don't sell anything where I need to accept sensitive information. On the other hand, my site at franklinveaux.com does have SSL because I have an ecommerce store there.
