guerrilla: a member of an irregular armed force that fights a stronger force by sabotage and harassment
Guerilla Marketing is the title of a book that offers suggestions on how to market something on the cheap. There are lots of eBooks that offer "secrets" on how to make money with no money. But the reality is that one needs to spend some money to get somewhere. It's possible to get somewhere on the cheap though- but what you don't burn in cash you will make up with time.
As far as I know PigeonRank [google.com] is still alive and well. (Actually not all the same pigeons; there are replacements from time to time.)
It's my understanding that after the Google engineers got frustrated with the problems inherent in cloud computing they decided to drastically increase the number of Pigeon Clusters. The new Caffeine infrastructure is the result.
And now it's time to grab a book, this morning's leftover bagel and go around to the park to try to increase some of my sites' PR.
The idea behind guerrilla marketing is that you take easily available materials and channels to market yourself - and go past the "big players" who have a lot of budget but are often not agile enough to see and respond to opportunities.
So it's more of a mindset than any specific technique. And it's a great mind-set to cultivate, too.