as a software dev, what kind of stuff can I do with this?
https://beagleboard.org/project
https://www.hackster.io/beagleboard/
https://github.com/search?q=beagleboard&ref=opensearch
https://hackaday.com/tag/beagleboard/
It seems that the easiest way to get started is to use a microSD card.
EDIT: Here's a video for the Blue:
https://youtu.be/pTpUMajQS_U?t=170
Starting around 2:50, she shows opening up the onboard Cloud9 instance after plugging in the MicroUSB cable.