In short, it means you're creative with the way you approach marketing, business development and sales, When everyone else does x, you do y. You experiment and focus on steps that produce results.
I'm not sure if what I'm planning for my next two days in San Francisco qualifies as Guerrilla Tactics, but it's certainly working with a shoe string budget for marketing. I explain in the video below what gamble I'm taking and what I'm doing for the next...ohhhh...36 hours.
Check it out and let me know what you think.