What's in that folder that's marked "Bills" on your hard drive, in case your other half cracks your password (it's your birthday, dummy); but in actuality holds the wank-bank full of images of women that look exactly-not like your missus.
Pornography is extremely subjective in that not everyone will find something a turn on. Under no circumstances look at another blokes collection as it will likely contain one legged midgets dressed as rabi's in latex Cherie Blair masks sandpapering each others genitals while eating pork pies. Worse, it might contain Paris 'bonebag' Hilton's sex tape.
The Legal Bit
The legal definition of Pornography is, "Material which is liable to corrupt." Now that got me thinking (oo-err missus) if you were to be prosecuted for having an unfeasibly large porn collection what would happen if the judge had a good look at it. If he wasn't corrupted, it can't have been porn. If he was corrupted can he still send you to The Big House? Has anyone ever been sent down by a judge who happened to be having a wank at the time?
See also: Pornoland Confederation