I'm digging blockshopper.com

Reminds me to use an LLC next time I buy. And to prevent you nosy Streeteasy types from finding who is behind the LLC:

Use a different law firm than my company's regular firm
Give power of attorney to lawyer so his name is on all the signed documents, not mine
No phone listing
Confidentiality clause in contract with 6 figure damages for talking to shut up brokers
All utility bills in name of LLC

Anything else to prevent detection?

Nice find 23! I found a few of the search features are a little "buggy" and wouldn't run properly (crashing) but overall a great tool for researching comps. Tried to cross check a couple of results against ACRIS but of course it was down for some reason this morning. But just eyeballing a couple of sales it looks pretty much spot on.
Wonder how they got all that data?

It's easy to get the data on people. Check names on ACRIS filings against LinkedIn pages. Google the rest.

modern, I have a sub-specialty in celeb kids, and I've never yet signed a confidentiality clause -- I just don't know how you put that over on people.

However, discreet brokers are going to be discreet because we want more business. As far as public record, you're going to need the cooperation of the board to buy through a shell such as a trust, so you really want to make sure you pick out a building that's going to work with you, esp. if you want a co-op. They'll probably make you sign an occupancy rider so that only named XX and XY can actually occupy the unit.

You can also use a business manager that has multiple clients -- Then an outsider can see that all the documents are in the name of XX business manager, but which of his clients owns that? That should cover most of your privacy issues.

However, if you're really famous, your neighbors/Gawker are going to end up tattling on you.

ali r.
{downtown broker}