How does blockchain.info resolve adresses? I wonder how sites such as blockchain.info resolve the owners of public bitcoin addresses. For example, blockchain.info knows that the xkcd donation address 14FHqYSgA... belongs to xkcd.com. It is available at xkcd.com/bitcoin, but somebody must be crawling all websites searching for that folder, right?

I assume there is a directory where this kind of websites are stored so that blockchain.info can look it up. Where is it and is there a public API available?

Thanks!
There's no central directory for this information.  You could scrape the Blockchain list if you wished, but if you do so you're relying on the accuracy of their information.