[macspoofing]

>Spolsky's hard-line essentially says re-building your application from scratch is bad strategy.

I don't think Spolsky's position is as "hard-line" as you think it is. I always took it as a very very strong "rule-of-thumb". Every time a rewrite is proposed, it should sound warning bells in all stakeholder. And we're talking about a clean-room rewrite, and not a sub-module rewrite. Spolsky has no problem with rewriting and re-architecturing sub-pieces of an application.

Twitter is a great example of Spolky's philosophy. They had a big architectural and technology problem with Ruby and RoR, but they didn't do a clean-room rewrite with Java. Instead they tackled one sub-component at a time, and now they have something that rocks, but still allowed them to keep the time/code investment they made originally. Just as well, it allowed them to incrementally 'upgrade' their service.