"Guerilla Marketing" is a term coined by the prolific author & marketing strategist, Jay Conrad Levinson.
It refers to low-cost, high-impact marketing strategies that you can use, which may require you getting your hands dirty, down in the trenches... so to speak.
Does it produce results? Yes, just like anything else, if properly applied. He has tons of books on "Guerilla Marketing" for XYZ or ABC.... whatever specific topic or industry you are in: Home Business, for Consultants, with Technology, etc.
He has a licensing program for other marketing professionals who want to use his brand and teach his material.
I ran a "Guerilla Marketing" with Social Media bootcamp back in 2009. The results that the participants got varied by the effort they put in to application of what was shared, but overall, "Guerilla Marketing" tactics, when used with intention, get tremendous results. (At minimum, a marketing campaign should return $3 for every $1 spent... We saw client exceed this *many* times over)