This is how much the world has changed in the last few years: Flow Kana, an on-demand medical marijuana delivery platform, has created a system that enables buyers to communicate with growers via social networks like Facebook and Twitter. Flow Kana, which launched today, makes it easy to get convenient deliveries of organic, sustainably grown pot. For now, it is only serving the San Francisco Bay Area, but it says it is hoping to quickly expand to other parts of California and potentially to other states where medical pot is legal.