First, anonymity is a useful tool on the Internet, even for non-criminals. It helps protect you against criminals, governments, corporations, and other entities who may want to globally identify and track you.
Second, all a bad guy needs is a single credential and he's got access to everything of yours, from your banking, to your spanking (porn memberships), to dating sites, to family pictures, email, etc. I don't know about you, but I have separate credentials for everything and beyond that, I like to maintain separate personas between my work and personal life, and heck, even facets of my personal life.
There are opt-in sort of things for this that largely meet your desires, such as Open ID or your Facebook login. What about those don't work for you?
That's what you mean, right?
Regarding giving each individual a unique URL, that's the idea behind OpenId.
Or more politely, this doesn't solve a problem I have.
Internet has evolved to such a point where we should throw out the old plumbing we built it all on, and make what has proven to be the common use cases. "place food subway" and "person mary jones text" seem like more logical ways to map the human brain onto the internet hive mind. the internet should have a built-in drop down menu search for all the things you might select from any type of data categorized as humans would
Unless I misunderstood your model