Another curious question from me. How deep would a page have to be in folders to be considered too deep?

Unless you are running a dynamic site (throws off SE spider sometimes), a purely html page-based site can go quite deep.

Originally Posted by checksum

Another curious question from me. How deep would a page have to be in folders to be considered too deep?

When its difficult for you to remember. If you cant remember your users will never.

In terms of usability, more than 3 may be user unfriendly.

I'm not sure there are any hard and fast rules, but 3 or 4 levels deep is probably about as far as you need to go. I'm sure there are sites that go deeper, but at some point that url is going to be really long and if you need to go deep it might make more sense to have some folders that are children become siblings one level up.