This is related to the way the server redirects incoming traffic to the site's root doc. In some cases of virtual hosting, you need to specify the trailing / to explicitly direct to the root document of the virtual site.
Saying www.yoursite.com/ is the same as saying [yoursite.com...] or whatever you have in your server config.
Without the trailing slash you are asking the server to do a redirect (which it will happily do). However your visitor might not like it - for example some spiders don't like to encounter a redirect at the root document level.
Use the trailing slash with no penalty, or if it is inside an href specify the actual file e.g. http*www.yoursite.com/index.html
[edited by: martinibuster at 7:32 am (utc) on May 23, 2004] [edit reason] url edit. [/edit]