Sure, if it's a small feature that fits in well with the existing structure. But Tbray's talking like people can just knock up facebook or basecamp from scratch

Sure, if it's a small feature that fits in well with the existing structure. But Tbray's talking like people can just knock up facebook or basecamp from scratch, in a matter of days. No-one can do that. Oh yeah sure, you might be able to make a decent stab at re-implementing one of them in a few days but it's a different story when you have to just make it up. Anyway I do agree with him generally, just that I see this stuff a lot. Good web developers are stunningly productive compared to your average .NET corporate seat-warmer but they're not magic!