I remember reading this story on the internet a few years ago. It told the story of how humans defeated an alien invasion using scams. There were no characters, it was more like a documentary piece. One of the events that I remember had to do with humans using a phony telethon and I think the Nigerian scam to make money behind the aliens back. The story incorporated several famous internet scams in it.
I've found it. It is called Planetary Defences by S. R. Algernon, it can be found here
Turns out it wasn't a documentary, but a subordinate describing events to his superior.