Great essay that points out, I think, the strength of Joel's system. The author cites the primary weakness of the system as being that it doesn't translate to non-programmers. He also (correctly, as far as I know) points out that Joel has the advantage of only really having to worry about programmers.

But then, I think that's the whole point of Joel's system. Sales people are paid on commission because it's a direct reflection on their skills. Likewise, I think that assistants and tech support staff probably should be allowed to negotiate since negotiation is a key skill to their position. Where Joel's system works is that a programmer's primary skill set does not involve selling and does not require negotiation/interpersonal skills (at least, not as a primary concern).

I think the only problem the author really had (aside from the apparent disinterest in seeing the system through) was one of messaging.