What about this... The owner of a website puts a file on their website called bitcoin_tags.json or something like that. This would server a similar purpose to sitemap.xml but instead contains a number of bitcoin addresses and labels.
For example http://wikileaks.org/bitcoin_tags.json
{
"tags" : {
"address" : "1HB5XMLmzFVj8ALj6mfBsbifRoD4miY36v",
"tag" : "Donations",
"sig" : "signature of concatenated tag and domain"
}
}
Once the owner of a website has added the file they can suggest that blockchain.info indexes it, once indexed blockchain.info will display the new tag accordingly. This has the advantage of.
* maintainable, webmaster can update bitcoin_tags.json as they choose. Deadlinks will be removed from the database.
* Decentralised, any service can index tags.
* More secure, both the domain and the address signature is verified. Tags can be independently verified if necessary and little moderation is needed.
For example http://wikileaks.org/bitcoin_tags.json
{
"tags" : {
"address" : "1HB5XMLmzFVj8ALj6mfBsbifRoD4miY36v",
"tag" : "Donations",
"sig" : "signature of concatenated tag and domain"
}
}
Once the owner of a website has added the file they can suggest that blockchain.info indexes it, once indexed blockchain.info will display the new tag accordingly. This has the advantage of.
* maintainable, webmaster can update bitcoin_tags.json as they choose. Deadlinks will be removed from the database.
* Decentralised, any service can index tags.
* More secure, both the domain and the address signature is verified. Tags can be independently verified if necessary and little moderation is needed.
You should only trust tags fetched via https, otherwise a man-in-the-middle could hijack the .json file and replace the address and signature.
(and I think you'd want "tags" to be an Array of Objects...)
RE: adding data to the blockchain: Did you see Stefan Thomas' nifty idea for using ECC math to tie a hash to a transaction without any blockchain bloat?