No, it's not just ASCII text. Only miners (like Satoshi's headline in the genesis block and Kaminsky's ASCII Bernake) are able to include ASCII data in blocks, everyone else needs to somehow encode it in transaction data.
err, yes it is just ASCII text. I suggest you run "strings" over the blockchain yourself, which I have done. If it wasn't I doubt anyone would find it.
I don't know if they used Kaminsky's technique or something else but it is plain text.
