I found them very effective. But I don't ask people to pay, I ask for feedback. If the software is good, they'll want to use it anyway!
People are willing to help if you are equally open about what the software can and cannot do. I implemented several features straight out of what people said they wanted through email, and the product was noticeably better for it.
I've also had people not respond at all or react strangely.
RethinkDB uses custom abstractions to hide the lower-level OS-specific code. We were able to port the low-level code to Windows with very little changes in these abstractions, and thus minimal changes to the rest of the code base.
The proper way to use libuv would be to replace those abstractions with libuv's own, which would affect a lot more code and possibly break a lot of implicit invariants.
In retrospect, perhaps we should have given alternatives like libuv, libevent or boost::asio more consideration.
Besides challenging the mind over matter, this work also challenges the idea of what to believe and pursue when scientific evidence is relatively lacking.
I have not - once the pain subsided I decided to take a break from all the medical reading and research for a while. Still, I'd definitely be interested in checking those out when I have a bit more free time.
Does this mean an actual truck, a vehicle? Did they accidentally hurt someone?
I liked this quote: The future for the dark side looks bright.