[chadcf]

I think just saying don't use python where speed is important is missing the whole point of this slideshow. The author is saying, hey, if we thought about this and put in a few different features we could make it a lot faster without programmers having to do much other than use an alternate implementation of some data stuctures.

While I'd agree that for 99% of us we're not going to find python/ruby/php/javascript to be a bottleneck that can't be mitigated, that's no reason to say it's not worth trying to make them faster. If we can make changes to these languages that will make them more efficient, why not do it?