You might conclude that the only real option is to buy a positive pressure fresh air system, but this comparison doesn't match my experience. I have no trouble driving the PM2.5 very close to 0 with a few standalone purifiers in my house (verified with a couple air quality monitors) even during bad wildfire smoke events. I'll grant I live in a modern house which is pretty well sealed, but it's also a question of sizing the purifier to the room's size and drafts.
There are some orthogonal advantages and disadvantages though. On the upside, you'll reduce CO2 and other pollutants from inside your house -- it can get quite stuffy when you can't ventilate due to poor outdoor air quality. A downside is that it may also bring in air at a different temperature or humidity than you'd like (though that can also be controlled to some extent with a HRV/ERV.)
I think you've mixed up relative and absolute differences. Both of your examples are in terms of absolute percentage points (pp, sometimes ambiguously labeled %), but relative changes are measured in percent (%). 300% relative difference just means 300/100 = 3x.
I enjoyed reading some of their results. I see some methodological issues here, however:
1) The test makes you distinguish between real words and a set of words they've made up in some way. As others have pointed out, some of them are pretty obvious non-words. I would expect the results to change depending on the method used to generate non-words.
2) Measuring the performance of a binary classification is a well studied problem with many metrics and approaches to quantifying performance (http://en.m.wikipedia.org/wiki/Binary_classification#Evaluat...). Subtracting the false positive rate from the true positive rate is not among them. The final score is not a consistent estimator of the fraction of words in their corpus you know.
I think linking accounts to debit cards is pretty valuable on it's own. It opens the door to making payments for a lot of people much easier down the road.
I think they've done something quite clever by (I infer) getting people to join up when they receive money. Venmo puts up an unnecessary wall by requiring that the payee sign up before they can be paid.
This is true, but there's a lot to be said for native libraries which can be used more naturally. More important for things like frameworks, etc. than algorithms / highly technical code. e.g. using the Python wrapper for OpenCV is fine -- a little bit jenky but it works, and I definitely don't want to write those myself if I'm focusing on a product. On the other hand, would you want to use a wrapper for a web framework written in C? Probably not.
"In academic research and in entrepreneurship, you need to multiply your effectiveness as a programmer, and since you (probably) won't be working with an entrenched code base, you are free to use whatever language best suits the task at hand."
What about libraries and code-bases available to the programmer? Legacy code might not be a concern, but what about having to reinvent wheels?
"With the visibility API, you can gracefully pause or degrade the timer to a much longer poll when the tab is in the background."
Note that this is already enforced for setInterval in some browsers -- I think Chrome changes the minimum interval to 1000ms from 4ms when the tab is in the background.
"Have we become so culturally invested in the allure of the Free Agent, the lone wolf, the techno-rebel with a cause, that we are prepared to shower millions of dollars (maybe tens of millions) on a small number of superstars rather than a well-assembled team that may not dazzle with individual brilliance, but overwhelms with collective capability?"
Who said it was about free agents? Those 5 aren't going to code alone, they're going to be working with 4 other people. And they're going to be much better at that too.
There are some orthogonal advantages and disadvantages though. On the upside, you'll reduce CO2 and other pollutants from inside your house -- it can get quite stuffy when you can't ventilate due to poor outdoor air quality. A downside is that it may also bring in air at a different temperature or humidity than you'd like (though that can also be controlled to some extent with a HRV/ERV.)