The Guerilla Marketing series are all good- by Jay Levinson. As is the oldie but goodie 'Permission Marketing' by Seth Godin.
Also recommended in this reply
Typographic jacket · original cover not fetched
A BOOK SERIES · 2006–2026 SAMPLE
Topics are model-inferred labels.
THE WORD OF MOUTH
Original Hacker News comments, in the readers’ own words.