I have to say, I disagree. Bitcoin can be anonymous *if used correctly*, otherwise it is not. If this guy wants just to trawl public webpages and categorize publicly available information, then he's not doing anything unlawful. Of course, if he decides to hack MtGox to get the user<->userid database, well, that'd be different. And in that sense, he'll be at a disadvantage compared to LE.
All it takes is for just one of the people you trade with to reveal their identity, and that will lead straight to you. Now if you've passed your received coins through a mixer after *every single transaction*, then maybe they won't be able to associate any one of your transactions with any other. Otherwise, you're on the hook. And I'd be willing to bet that unless a majority of users take pains to hide their identity, then just about everyone will be visible to data mining.
I agree with OP - better that something like this be done in the open, so everyone can see how anonymous they are; otherwise everyone is just falling for the usual internet=anonymous delusion. In fact, perhaps it would be good to offer a bounty to whoever can do the work, and present it as a navigable flow of interconnected and joined addresses and users (where known). And then - yeah, see what could be done to the protocol to improve anonymity. Like each block includes a built-in mixer, say.
IIRC there are several requirements for you to remain anonymous:
1. Never mix money from different receiving addresses - i.e. each wallet must have only one receiving address
2. Pass all received money through a mixer
3. Connect to bitcoin (and pools, exchanges etc) only through tor, and give them no personally identifying information.
4. Never publish your bitcoin address
5. Anything else?
Of course, you gotta hope that the mixer op doesn't sell you out. Or else do multiple passes through multiple mixers... losing x% each time.
Frisco- no offense mate, but hugely bad idea in my book. And I will take the signal honor of being the first to opt out of your monitoring or reverse engineering any data whatsoever on any transaction of mine, and if you are found to be doing so, I will pursue remedies available to those who have been illegally wiretapped. Gathering this kind of data and making it available for others to consume without a warrant violates all kinds of interesting laws in a variety of countries and will open you and whatever business model you want to release it under to a staggering amount of liability.