In an effort to "track the chain" I wonder if there are any Bitcoin web crawlers that specifically look for Bitcoin addresses.
Following on to that question, are there any groups/volunteers/ people using that information to compile a dossier on who has what address?
Well Google, or any other search-engine, already crawls the Web for you. Probably just Googling an address will lead you to the Website where its owner published it, and it'll allow you to find other relevant information related to that address. This of course assuming the publisher of the website actually owns that address.
The only real way to prove that someone owns an address is for them to actually sign a transaction using that address - in other words: they can prove to you they own an address by making a payment of a specific amount using that address.
This is ongoing area of research and there are a number of companies working on this. You can find a list here. The problem with this is that people can mix coins and it becomes difficult to accurately ascertain identity. Two simple tools which you can try out:
It might be useful to note that Blockchain.info has a list of "Address tags": public bitcoin addresses that have an annotation indicating something about the identity of the owner.
This is an opt-in database of public addresses where the owner has chosen to submit the public address and a corresponding "tag" (human-meaningful name) to Blockchain.info. See https://blockchain.info/tags.
This is much narrower than what you are looking for, but might be useful for some purposes.
bitcoinwhoswho.com crawls for addresses and associates them with urls in order to create a dossier like the one you mention in your original post
