[meow]

The article was mentioning md5 hashes of songs to find the matches. Besides, its not a question of whether the system can be foolproof.

[carbonica]

But what I pulled out from the Wired article amounted to "it's silly that if the file sizes are slightly different you need to upload your whole song." If file sizes are different, the MD5 will be wrong in nearly all cases. They're talking about something different in that paragraph than you are.