Hehe, that depends ;)
The first looks to me like a name, whereas the second looks like a URL.
But the domain name is less of an issue, since mixed-case hostnames will not stop a user from reaching a URL. But mixed-case filenames often will. WebmasterWorld.com is fine, but WebmasterWorld.com/Google/ is an error page.
In a case-insensitive world, you could brand URLs however you liked and not have any problem. The W3C and search engines opted for case sensitivity, and so most sites will return errors if you change letter casing. At a minimum, if you perceive an advantage in mixed-case filenames you need to account for usage of incorrect letter casing since you're likely teaching users to use whatever case they like.