My boss would send me out with a list of sites, a map and a Polaroid camera, and I'd have to verify that all the posters we'd bought were actually up.
Sometimes this would involve a pleasant day of Tube travel and walking, sometimes a drive around a new town. It appealed to the flaneur in me and, given the tiny wages I got as a media assistant and the rebates we always got, it was probably a reasonable investment.
I was always surprised by how often a poster site we were being charged for didn't actually exist. (This, I hasten to add, was about 20 years ago. I'm sure that doesn't happen now. Obviously.) I also remember, fondly, the endless conversations we had with leaflet distribution companies as our dealer network clients reported the discovery of huge piles of leaflets in hedges.
It has always been a fascinating side of media - the cheating, the abuse, the perverse incentives that drive unscrupulous behaviour.
And that's often the most fascinating bit of new media, too - the ingenious ways people find to pump up their numbers in a world where most people don't understand the numbers anyway.
If you're interested in this stuff, there's a fascinating blog post called "The Twitter Underground Economy", written by Baracuda Networks, an IT and security company.
It attempts to delve into the economics of fake Twitter accounts and reveals, among other things, that there are about 20 dealers on eBay selling Twitter followers. You can buy 1,000 followers for between $2 and $55, individual dealers can control as many as 150,000 Twitter accounts, and you can get 2,000 retweets for a mere $5. Not really surprising, I guess, but it's nice to know the numbers and it's the little details that make these things interesting.
Twitter, itself, is constantly at war with these fake accounts, detecting and deleting as many as it can, and that accounts for the price variation for followers. Pay $2 per 1,000 and you get pretty obvious fakes, highly likely to be deleted. Pay more and you get something more human. It's all a bit sci-fi, isn't it?
This whole world has risen to prominence recently because the Republican nominee Mitt Romney had a sudden and substantial spike in his Twitter following, and thousands of these followers turned out to be fake. Which means either his staff's done something silly, or someone's set him up.
Either is equally possible - there's really no way of knowing.
All of which is largely of academic interest, of course. I'm sure you're not silly enough to set something like follower numbers or retweets as a media strategy metric.