The days of rolling joints are coming to an end. In 2017, more and more people are choosing to consume marijuana electronically.

People use electronic vaporizers with cannabidiol (CBD)-rich hemp oil while attending the International Cannabis Association Convention in New York Thomson Reuters

Just like so many things about life in the post-smartphone world, cannabis is being made more convenient and accessible through modern technology. Rather than buying cannabis, rolling a joint, and burning plant matter, more and more people are turning to vaping — a far easier, more modern way to consume cannabis. You simply purchase plant matter or a small cartridge of oil (depending on the vaping device), load it into an inexpensive pen, and you're ready to go.

The Bloom Farms "Highlighter" is a simple, inexpensive vape pen that can be used with exchangeable cartridges. Bloom Farms

As laws allowing adult cannabis use continue to pass in states across the US, cannabis oils, in particular, have increased in popularity — and they're sure to continue on that path. It's easy to see why: They're inexpensive, easy to use, and discreet. In California, the largest state economy in the US, companies like Bloom Farms and Dark Heart are pioneering leaders in the cannabis oil market. Their products look just like the easy-to-use, crowd-friendly vaporizers seen above.

But what in the world is cannabis oil? How is it made? Is it safe? Here's what we know about cannabis oils, the future of mainstream cannabis use.