A jambassador is a promoter ("ambassador") for the jam session community ("jam" or "jam session"). Jambassador is also the nickname for the ambassadors for the music jam session platform "jambassador.com". Jambassadors run around and talk about, blog, post and promote the idea of musicians from all over the world peacefully jamming together on that platform.
A jambassador spreads the word of music!
An over-the-top fanatic of Jamba Juice, aggressively promoting the dietary benefits to anyone within earshot. Typicallt sneers at diets of energy drinks, Good & Plentys, licorice, and donuts.
Pam: You really should give up the Monster drinks and switch to something healthy, like Jamba Juice.
Mark: Wow. You're such a Jambassador. Give it a rest.