John Berfelo just posted a great video on how different humidity levels effect yields when squishing nugs (aka rosin pressing). This is key when making solventless dab. This is great information because not much knowledge is spread on this topic and while hydrocarbon extractions using butane or propane remain mainstream. Rosin doesn't require an expensive closed loop extraction setup or the dangers of open blasting. It's simply too dangerous and not worth the legal implications that may come with it. He uses a cannaclamp which seems great, most people just use a hair straightener and a vice grip.
Personally I am looking forward to my endeavors using this technique because it will be much easier to be in compliance with the laws in legal states, I'm not using fossil fuels, it still does very well to preserve terpenes, it's much safer, less expensive, can easily be stable at room temp, and nearly instant. A downside is mass production although I'm sure somebody has or is figuring that out.
What I would like to see and/or try is getting the humidity levels dialed in and squishing bubble hash along with dry sift. Also mixing different types of PEG and making some really good cartomizers for vaping while possibly reintroducing different types of terpenes for flavor, aroma, and effects.
Dab on!