The price of something has nothing to do with the content. The data that represents the price is a pointer to the content, akin to affixing a new price sticker to the jacket of a book. Perhaps the original published content could have a recommended price embedded in it.
This applies to the names and categorizations of things as well.
As for updates, imagine you're a shopkeep and in the morning you publish a table of prices, titles and content-addressable hashes.
Now, for the whole naming-of-the-things... take your pick: ICANN or Namecoin-like.
Claim ownership of a top-level name and then you can point it at whatever you want.
This applies to the names and categorizations of things as well.
As for updates, imagine you're a shopkeep and in the morning you publish a table of prices, titles and content-addressable hashes.
Now, for the whole naming-of-the-things... take your pick: ICANN or Namecoin-like.
Claim ownership of a top-level name and then you can point it at whatever you want.